datavorous/entrance-exam-dataset huggingface dataset:
Which of the following receptors are specifically responsible for maintenance of the balance of body and posture?

Options:
A Basilar membrane and otoliths
B Hair cells and organ of Corti
C Tectorial membrane and macula
D Crista ampullaris and macula

The correct answer is:
Crista ampullaris and macula

Solution:
The inner ear contains crista ampullaris and macula as the specific receptors of the vestibular apparatus responsible for maintenance of balance of the body and posture.

Topic: Biology, Neural Control and Coordination, NEET, NEET 2019 (Odisha)
Which of the following reduction reaction CANNOT be carried out with coke?

Options:
A Al2O3→Al
B ZnO→Zn
C Fe2O3→Fe
D Cu2O→Cu

The correct answer is:
Al2O3→Al

Solution:
Reduction of Al2O3→Al is carried out by electrolytic reduction of its fused salts. ZnO, Fe2O3 and Cu2O can be reduced by carbon.

Topic: Chemistry, General Principles and Processes of Isolation of Metals, JEE Main, JEE Main 2021 (16 Mar Shift 2)
Which of the following regent can effectively carried out the following conversion?

Options:
A \( \mathrm{LiAlH}_{4} \)
B \( \mathrm{NaBH}_{4} \)
C Raney \( \mathrm{Ni} \)
D None of these.

The correct answer is:
\( \mathrm{NaBH}_{4} \)

Solution:
NaBH4 is a mild reducing agent and can not reduce less reactive ester group

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following relation is not correct?

Options:
A ΔH=ΔU-PΔV
B ΔU=q+W
C ΔSsys+ΔSsurr≥0
D ΔG=ΔH-TΔS

The correct answer is:
ΔH=ΔU-PΔV

Solution:
Enthalpy, in a thermodynamic system, is the measure of its energy which is equal to the sum of the internal energy and the product of its pressure and volume.

H = U+PV (By definition)

ΔH=ΔU+ΔPVor ΔH=ΔU+VΔP+ PΔV

at constant pressure

ΔH=ΔU+PΔV So, option A is incorrect.

ΔU=q+W First law of thermodynamics.

ΔSsys+ΔSsurr≥0 or ΔSUniverse ≥0 A form of second law of thermodynamics.

ΔG=ΔH-TΔS Second law of thermodynamics.

Topic: Chemistry, Thermodynamics (C), JEE Main, JEE Main 2022 (28 Jul Shift 1)
Which of the following relation is true, if:
- Equal amount of charge of electricity in coulomb is passed through aqueous solution of \( \mathrm{AX} \) and \( \mathrm{BX}_{2} \).
- Number of moles of \( \mathrm{A} \) and \( \mathrm{B} \) deposited respectively are \( \mathrm{Y} \) and \( \mathrm{Z} \).

Options:
A \( \mathrm{Y}=\mathrm{Z} \)
B \( \mathrm{Y} < \mathrm{Z} \)
C \( \mathrm{Z}=2 \mathrm{Y} \)
D \( \mathrm{Y}=2 \mathrm{Z} \)

The correct answer is:
\( \mathrm{Y}=2 \mathrm{Z} \)

Solution:
A + + e â âA B 2+ +2 e â âB
net n coulombs of electricity is passed through the aqueous solution
â´no of moles of A deposited=Y mole=n
no of moles of B deposited=n/2=Z mole
â´Y2=Z
Y=2Z

Topic: Chemistry, Electrochemistry, JEE Main
Which of the following relation represent Biot-Savart's law?

Options:
A $\mathrm{d} \overline{\mathrm{B}}=\frac{\mu_0}{4 \pi} \frac{\overline{\mathrm{d}} \times \overline{\mathrm{r}}}{\mathrm{r}}$
B $\mathrm{d} \overline{\mathrm{B}}=\frac{\mu_0}{4 \pi} \frac{\overline{\mathrm{d}} \mathrm{l} \times \hat{\mathrm{r}}}{\mathrm{r}^3}$
C $\mathrm{d} \overline{\mathrm{B}}=\frac{\mu_0}{4 \pi} \frac{\overline{\mathrm{d}} \times \overline{\mathrm{r}}}{\mathrm{r}^3}$
D $\mathrm{d} \overline{\mathrm{B}}=\frac{\mu_0}{4 \pi} \frac{\overline{\mathrm{d}} \times \overline{\mathrm{r}}}{\mathrm{r}^4}$

The correct answer is:
$\mathrm{d} \overline{\mathrm{B}}=\frac{\mu_0}{4 \pi} \frac{\overline{\mathrm{d}} \times \overline{\mathrm{r}}}{\mathrm{r}^3}$

Solution:
$d \vec{B}=\frac{\mu_0}{4 \pi} \frac{I(\overrightarrow{d \ell} \times \vec{r})}{r^3}$

Topic: Physics, Magnetic Effects of Current, JEE Main
Which of the following relations are correct?
(A) ΔU=q+pΔV
(B) ΔG=ΔH-TΔS
(C) ΔS=qrevT
(D) ΔH=ΔU-ΔnRT
Choose the most appropriate answer from the options given below :

Options:
A C and D only
B B and C only
C A and B only
D B and D only

The correct answer is:
B and C only

Solution:
The Gibbs free energy can be written as a function of enthalpy and entropy as follows,

(B) G=H-TS

At constant T

ΔG=ΔH-TΔS

(A) According to first law of thermodynamics, ΔU=Q+W

If we apply constant P and reversible work.

W=-P∆V

ΔU=Q-PΔV

(C) By definition of entropy change dS=dqrevT

At constant T

ΔS=qrevT

Enthalpy can be written as a function of internal energy, pressure and volume as follows,

(D) H=U+PV

For ideal gas equation, PV=nRT

H=U+nRT

At constant T

ΔH=ΔU+ΔnRT

Topic: Chemistry, Thermodynamics (C), JEE Main, JEE Main 2023 (29 Jan Shift 2)
Which of the following relations are functions? Give reasons. If it is a function, determine its domain and range.
(i) $\{(2,1),(5,1),(8,1),(11,1),(14,1),(17,1)\}$.
(ii) $\{(2,1),(4,2),(6,3),(8,4),(10,5),(12,6),(14,7)\}$.
(iii) $\{(1,3),(1,5),(2,5)\}$.

Options:

None

Solution:
(i) It is a function because to each first element of the ordered pair, there corresponds exactly one second element.
Domain $=\{2,5,8,11,14,17\}$
Range $=\{1\}$
(ii) It is a function because to each first element of the ordered pair, there corresponds exactly one second element.
Domain $=\{2,4,6,8,10,12,14\}$
Range $=\{1,2,3,4,5,6,7\}$.
(iii) It is not a function because the two ordered pairs $(1,3)$ and $(1,5)$ have the same first component.

Topic: Mathematics, Relations and Functions (Class 11)
Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?

Options:
A $p^{1-\gamma} T^{\gamma}=$ constant
B $p V^{\gamma}=$ constant
C $T V^{\gamma-1}=$ constant
D $p^{\gamma} T^{1-\gamma}=\mathrm{constant}$

The correct answer is:
$p^{\gamma} T^{1-\gamma}=\mathrm{constant}$

Solution:
For adiabatic process,
$p V^{\gamma}=$ constant
For an ideal gas, $p V=n R T$ or $p=\frac{n R T}{V}$
Again, from ideal gas equation,
$$
\begin{aligned}
V &=\frac{n R T}{p} \\
\Rightarrow \quad p\left(\frac{n R T}{p}\right)^{\gamma} &=\text { constant } \\
\Rightarrow \quad p^{1-\gamma} T^{\gamma} &=\text { constant }
\end{aligned}
$$
Hence, relation shown in option (d) is not for adiabatic process.

Topic: Physics, Thermodynamics, JEE Main
Which of the following relationship is correct, where $r$ is the rate of diffusion of a gas and $d$ is its density

Options:
A $r \propto \sqrt{1 / d}$
B $r \propto \sqrt{d}$
C $r=d$
D $r \propto d$

The correct answer is:
$r \propto \sqrt{1 / d}$

Solution:
$r \propto \sqrt{1 / d}$
Graham's law of diffusion of gases: It states that the rate of diffusion if different gases are inversely proportional to the square root of their densities at constant temperature and pressure.
Mathematically, Graham's law is
(1) $r \propto \sqrt{1 / d}$

Topic: Chemistry, States of Matter, JEE Main
Which of the following relationship when graphed give a rectangular parabola for helium gas?
I. KE vs T at constant P and V
II. V vs 1T at constant P and n
III. P vs V at constant T and n

Options:
A III
B I and III
C II
D II and III

The correct answer is:
II and III

Solution:
Graph of P vs V at constant T is a rectangular parabola.
Graph of V vs 1T at constant P and n is a rectangular parabola.
Kinetic energy ∝T
Hence a graph between KE v/s T will be in straight line.

Topic: Chemistry, States of Matter, JEE Main
Which of the following remains constant during skeletal muscle contraction?

Options:
A H band
B I band
C A band
D Region between Z-lines

The correct answer is:
A band

Solution:
During muscle contraction :
1. 'I' band - Decreases.
2. 'A' band - Remains constant.
3. 'H' band - Decreases.
4. Length of Actin (thin filament) and myosin (thick filament) -remains constant.
5. Heat is produced.

Topic: Biology, Locomotion and Movement, NEET
Which of the following remains constant for a projectile fired from the earth ?

Options:
A Momentum
B Vertical component of velocity
C Kinetic energy
D Horizontal component of velocity

The correct answer is:
Horizontal component of velocity

Solution:
There is no acceleration in the horizontal direction during projectile motion and only gravitational acceleration \(g\) works in vertically downward direction. Hence, horizontal component of velocity remains constant.

Topic: Physics, Motion In Two Dimensions, AP EAMCET, AP EAMCET 2020 (21 Sep Shift 2)
Which of the following representations shows the pyramid of numbers in a forest ecosystem?

Options:
A $\mathrm{D}$
B $\mathrm{A}$
C $B$
D C

The correct answer is:
$B$

Solution:
Pyramid of number is spindle-shaped in a forest ecosystem because producers are mainly large trees which are less in number. Primary consumers like birds, deer, elephant, etc, are more in number than the producers, then the number of secondary consumers and tertiary or top consumers gradually decreases.
Pyramid of number is inverted for parasitic food chain in a single tree ecosystem.

Topic: Biology, Ecosystem, NEET, NEET 2010 (Mains)
Which of the following represents a chelating ligand

Options:
A \( \mathrm{H}_{2} \mathrm{O} \)
B \( \mathrm{OH}^{-} \)
C DMG
D \( \mathrm{Cl}^{-} \)

The correct answer is:
DMG

Solution:
DMG is Dimethylglyoxime. In chelating ligand, central atom forms a ring like structure. Because DMG is a polydentate ligand which binds the central atom nickel forming a ring like structure, it represents a chelating ligand.

Topic: Chemistry, Coordination Compounds, JEE Main
Which of the following represents a diploid structure?

Options:
A Sporophyte and capsule of moss
B Gametophyte, archegonia and egg of moss
C Gametophyte, antheridia and sperm of moss
D Sporophyte and spore of moss

The correct answer is:
Sporophyte and capsule of moss

Solution:
In moss the main plant body is haploid gametophyte and after sexual reproduction it produces diploid sporophyte which consists of foot, setae and capsule. Capsule consists of diploid sporogenous tissue which undergoes meiosis to form haploid spores.

Topic: Biology, Plant Kingdom, NEET
Which of the following represents a plot of compressibility factor (Z) versus P at room temperature for helium?

Options:
A
B
C
D

The correct answer is:

Solution:
'He' is less compressible than ideal gas because repulsive forces are dominant (Z > 1).
For ne (a = 0)

Topic: Chemistry, States of Matter, JEE Main
Which of the following represents clear electropositive properties

Options:
A F
B Cl
C Br
D I

The correct answer is:
I

Solution:
Iodine has electropositive properties.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following represents correctly the changes in thermodynamic properties during the formation of an ideal binary solution:

Options:
A
B
C
D

The correct answer is:

Solution:
For ideal solution:
PTexp=PAοXA+PBοXB
A−−−B = A−−−A B−−−B
ΔHmix=0,ΔVmix=0,ΔSmix=+ve,ΔGmix=-ve

Topic: Chemistry, Solutions, JEE Main
Which of the following represents the correct order of increasing electron gain enthalpy with negative sign for the elements $\mathrm{O}, \mathrm{S}, \mathrm{F}$ and $\mathrm{Cl}$ ?

Options:
A $\mathrm{Cl} < \mathrm{F} < \mathrm{O} < \mathrm{S}$
B $\mathrm{O} < \mathrm{S} < \mathrm{F} < \mathrm{Cl}$
C F $ < $ S $ < \mathrm{O} < \mathrm{Cl}$
D S $ < \mathrm{O} < \mathrm{Cl} < \mathrm{F}$

The correct answer is:
$\mathrm{O} < \mathrm{S} < \mathrm{F} < \mathrm{Cl}$

Solution:
Key Idea:- Electron gain enthalpy, generally, increases in a period from left to right and decreases in a group on moving downwards. However, members of III period have somewhat higher electron gain enthalpy as compared to the corresponding members of second period, because of their small size.
$\mathrm{O}$ and $\mathrm{S}$ belong to VI A (16) group and $\mathrm{Cl}$ and $\mathrm{F}$ belong to VII A (17) group. Thus, the electron gain enthalpy of $\mathrm{Cl}$ and $\mathrm{F}$ is higher as compared to $\mathrm{O}$ and $\mathrm{S}$.
$\mathrm{Cl}$ and $\mathrm{F}>\mathrm{O}$ and $\mathrm{S}$
Between $\mathrm{Cl}$ and $\mathrm{F}, \mathrm{Cl}$ has higher electron gain enthalpy as in $\mathrm{F}$, the incoming electron experiences a greater force of repulsion because of small size of $\mathrm{F}$ atom. Similar is true in case of $O$ and $S$ ie, the electron gain enthalpy of $S$ is higher as compared to $O$ due to its small size. Thus, the correct order of electron gain enthalpy of given elements is
$$
\mathrm{O} < \mathrm{S} < \mathrm{F} < \mathrm{Cl}
$$

Topic: Chemistry, Redox Reactions, JEE Main
Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ?

Options:
A Ba<Ca <Se<S<Ar
B Ca <Ba<S<Se<Ar
C Ca<S<Ba<Se<Ar
D S<Se<Ca<Ba<Ar

The correct answer is:
Ba<Ca <Se<S<Ar

Solution:
Ba < Ca < Se < S < Ar

Ba and Ca belong to group IIA ( alkaline earth metals).
Se and S belong to group Vl A (Chalcogens) and as we go down the group ionization enthalpy decreases with increasing atomic size. So,

Ba < Ca and Se < S
Ar has stable completely filled electronic configuration and, therefore, has the highest ionization enthalpy.Hence, the correct order is
Ba<Ca<Se<S<Arin kJmol−15035909419991520

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main, JEE Main 2013 (07 Apr)
Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ?

Options:
A Ba < Ca < Se < S < Ar
B Ca < Ba < S < Se < Ar
C Ca < S < Ba < Se < Ar
D S < Se < Ca < Ba < Ar

The correct answer is:
Ba < Ca < Se < S < Ar

Solution:
Ba < Ca < Se < S < Ar
Ba, Ca belong to gr IIA ( alkaline earth metals)
Se and S belong to gr Vl A (Chalcogens)
and as we go down the group ionaization enthalpy decreases with increasing atomic size. So,

Ba < Ca and
Se < S
Ar has stable completely filled electronic configuration and, therefore,has higest ionization enthalpy.Hence,the correct order is
Ba < Ca < Se < S < Ar in kJmol â1 503 590 941 999 1520

Topic: Chemistry, Classification of Elements and Periodicity in Properties, JEE Main
Which of the following represents the correct order of metallic character of the given elements?

Options:
A Si<Be<Mg<K
B Be<Si<Mg<K
C K<Mg<Be<Si
D Be<Si<K<Mg

The correct answer is:
Si<Be<Mg<K

Solution:
Group 1 elements are most metallic, as we go across the periodic table metallic character increases while going down the group and decreases along the period. Silicon is p-block element, potassium, beryllium and magnesium are s-block elements.

Topic: Chemistry, s Block Elements, JEE Main, JEE Main 2023 (25 Jan Shift 2)
Which of the following represents the correct order of the activity in the given compounds?

Options:
A CH 3 COOH >  BrCH 2 COOH >  ClCH 2 COOH >  FCH 2 COOH
B FCH 2 COOH >  CH 3 COOH >  BrCH 2 COOH >  ClCH 2 COOH
C BrCH 2 COOH >  ClCH 2 COOH >  FCH 2 COOH >  CH 3 COOH
D FCH 2 COOH >  ClCH 2 COOH >  BrCH 2 COOH >  CH 3 COOH

The correct answer is:
FCH 2 COOH >  ClCH 2 COOH >  BrCH 2 COOH >  CH 3 COOH

Solution:
The acidity of halogenated acids increases proportionately with the increase in electronegativity of the halogen present. Therefore, the correct order is
FCH 2 COOH >  ClCH 2 COOH >  BrCH 2 COOH >  CH 3 COOH

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following represents the correct range of Residual Volume?

Options:
A This averages 1200 mL to 2100 mL.
B This averages 1100 mL to 1200 mL.
C This averages 1000 mL to 1100 mL.
D This averages 2000 mL to 3000 mL.

The correct answer is:
This averages 1100 mL to 1200 mL.

Solution:
Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.

Topic: Biology, Breathing and Exchange of Gases, NEET
Which of the following represents the Freundlich adsorption isotherms?

(A)

(B)

(C)

(D)

Choose the correct answer from the options given below:

Options:
A

A, C, D only

B

A, B only

C

B, C, D only

D

A, B, D only

The correct answer is:

A, B, D only

Solution:
The equation xm=KP1/n represents Freundlich adsorption isotherm. It is an empirical relationship between the amount of gas adsorbed by a given amount of solid adsorbent surface and pressure of the gas at a particular temperature.

So, Freundlich adsorption isotherm equation is

xm=KP1/n

⇒logxm=logK+1nlogP

Extent of adsorption xm decreases with increase in temperature.

With the help of the above two equation, following plots are obtained

Topic: Chemistry, Surface Chemistry, JEE Main, JEE Main 2023 (08 Apr Shift 1)
Which of the following represents the given mode of hybridisation $s p^2-s p^2-s p-s p$ from left to right

Options:
A $\mathrm{H}_2 \mathrm{C}=\mathrm{CH}-\mathrm{C} \equiv \mathrm{CH}$
B $\mathrm{HC} \equiv \mathrm{C}-\mathrm{C} \equiv \mathrm{CH}$
C $\mathrm{H}_2 \mathrm{C}=\mathrm{C}=\mathrm{C}=\mathrm{CH}_2$
D $\mathrm{CH}_2$

The correct answer is:
$\mathrm{H}_2 \mathrm{C}=\mathrm{CH}-\mathrm{C} \equiv \mathrm{CH}$

Solution:
$\stackrel{s p^2}{\mathrm{CH}}{ }_2=\stackrel{s p^2}{\mathrm{C}} \mathrm{H}-\stackrel{s p}{\mathrm{C}} \equiv \stackrel{s p}{\mathrm{C}} \mathrm{H}$

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following represents the incorrect order of properties?

Options:
A NaCl<MgCl2<AlCl3<SiCl4
(order of ionic character)
B BeCO3<MgCO3<CaCO3<BaCO3
(order of thermal stability)
C LiH>NaH>KH>RbH>CsH
(order of thermal stability)
D BeSO4>MgSO4>CaSO4>BaSO4
(Order of solubility in water)

The correct answer is:
NaCl<MgCl2<AlCl3<SiCl4
(order of ionic character)

Solution:
Correct order of ionic character.
NaCl>MgCl2>AlCl3>SiCl4

Topic: Chemistry, s Block Elements, JEE Main
Which of the following represents the lattice structure of A0.95O containing A2+, A3+ and O2– ions?

A.

B.

C.

Options:
A B and C only
B B only
C A and B only
D A only

The correct answer is:
A only

Solution:
Applying the electrical neutrality principle in metal deficiency defect.

One A2+ is missing then two A2+ ions are converted into A3+ ion so 0.05 A2+ ion are missing and 0.05×2 A2+ ion are converted in A3+ ion so for each O2- ion total A2+ ion 0.85 and A3+ ion is 0.1.

Hence, A satisfies the condition.

Topic: Chemistry, Solid State, JEE Main, JEE Main 2023 (01 Feb Shift 1)
Which of the following represents the steps involved in developing GMOs?

Options:
A Identification of DNA with desirable gene.
B Introduction of identified DNA into the host.
C Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
D All the above

The correct answer is:
All the above

Solution:
For genetically modifying an organism, a specific desired gene needs to be isolated. This desired gene should be introduced in a specific host cell, where it can multiply and get transferred to all the progeny cells.

Topic: Biology, Biotechnology - Principles and Processes, NEET
Which of the following represents the structure of the principal product in the given reaction?

Options:
A
B
C
D

The correct answer is:

Solution:
When toluene is treated with an alkyl halide in the presence of anhydrous aluminium chloride, it gives alkyl toluene. In this reaction, hydrogen atom of benzene is replaced by an alkyl group. The reaction is called as Friedel-Craft's alkylation reaction. In this reaction, alkyl groups are electrophiles and the role of aluminium chloride is to generate these electrophiles.

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following resonating structures of 1-methoxy-1, 3-butadiene is least stable

Options:
A $\stackrel{8}{\mathrm{C}} \mathrm{H}_2-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\stackrel{\ominus}{\mathrm{O}}-\mathrm{CH}_3$
B $\mathrm{CH}_2=\mathrm{CH}_2-\stackrel{8}{\mathrm{C}} \mathrm{H}-\mathrm{CH}=\stackrel{\oplus}{\mathrm{O}}-\mathrm{CH}_3$
C \(\stackrel{\oplus~~~~}{\mathrm{CH}}_2-\stackrel{\oplus~~~~}{\mathrm{CH}}-\mathrm{CH}=\mathrm{CH}-\mathrm{O}-\mathrm{CH}_3\)
D $\mathrm{CH}_2=\mathrm{CH}-\stackrel{\stackrel{\Sigma}{\mathrm{C}}}{ } \mathrm{H}-\stackrel{\oplus}{\mathrm{C}} \mathrm{H}-\mathrm{O}-\mathrm{CH}_3$

The correct answer is:
\(\stackrel{\oplus~~~~}{\mathrm{CH}}_2-\stackrel{\oplus~~~~}{\mathrm{CH}}-\mathrm{CH}=\mathrm{CH}-\mathrm{O}-\mathrm{CH}_3\)

Solution:
The octet of all atoms are complete in structures (a) and (b). In structure (d) electron deficiency of positively charged carbon is duly compensated by lone pair electrons of adjacent oxygen atom while such neighbour group support is not available in structure (c).

Topic: Chemistry, General Organic Chemistry, JEE Main
Which of the following respiratory volume has the volume of 1100 mL to 1200mL?

Options:
A Tidal volume
B Inspiratory Reserve Volume
C Expiratory Reserve Volume
D Residual Volume

The correct answer is:
Residual Volume

Solution:
Tidal Volume (TV): Volume of air inspired or expired during a normal respiration. It is approx. 500 mL., i.e., a healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute.
Inspiratory Reserve Volume (IRV): Additional volume of air, a person can inspire by a forcible inspiration. This averages 2500 mL to 3000 mL.
Expiratory Reserve Volume (ERV): Additional volume of air, a person can expire by a forcible expiration. This averages 1000 mL to 1100 mL.
Residual Volume (RV): Volume of air remaining in the lungs even after a forcible expiration. This averages 1100 mL to 1200 mL.

Topic: Biology, Breathing and Exchange of Gases, NEET
Which of the following rods, (given radius $r$ and length $l$) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?

Options:
A $r=r_0 \quad l=l_0$
B $r=2 r_0 \quad l=l_0$
C $r=r_0 \quad l=2 l_0$
D $r=2 r_0 \quad l=2 l_0$

The correct answer is:
$r=2 r_0 \quad l=l_0$

Solution:
Heat conducted
$$
=\frac{K A\left(T_1-T_2\right) t}{l}=\frac{K \pi r^2\left(T_1-T_2\right) t}{l}
$$
The rod with maximum ratio of $\frac{A}{l}$ will conduct most. Here the rod $r=2 r_0$ and $l=l_0$ will conduct most.

Topic: Physics, Thermal Properties of Matter, JEE Main
Which of the following rods, (given radius $r$ and length $l$) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?

Options:
A $r=r_0 \quad l=l_0$
B $r=2 r_0 \quad l=l_0$
C $r=r_0 \quad l=2 l_0$
D $r=2 r_0 \quad l=2 l_0$

The correct answer is:
$r=2 r_0 \quad l=l_0$

Solution:
Heat conducted
$$
=\frac{K A\left(T_1-T_2\right) t}{l}=\frac{K \pi r^2\left(T_1-T_2\right) t}{l}
$$
The rod with maximum ratio of $\frac{A}{l}$ will conduct most. Here the rod $r=2 r_0$ and $l=l_0$ will conduct most.

Topic: Physics, Thermal Properties of Matter, NEET, NEET 2005
Which of the following salts is the most basic in aqueous solution?

Options:
A PbCH3COO2
B AlCN3
C CH3COOK
D FeCl3

The correct answer is:
CH3COOK

Solution:
Salt of Pb(OH)2+ CH3COOH
Weak base Weak acid

Salt of   Al(OH)3+HCN
Weak base Weak acid

Salt of Fe(OH)3+HCl
Weak base Strong acid
Hence, the nature of the solution is basic.

Topic: Chemistry, Ionic Equilibrium, JEE Main, JEE Main 2018 (08 Apr)
Which of the following salts undergoes hydrolysis

Options:
A $\mathrm{CH}_3 \mathrm{COONa}$
B $\mathrm{KNO}_3$
C $\mathrm{NaCl}$
D $\mathrm{K}_2 \mathrm{SO}_4$

The correct answer is:
$\mathrm{CH}_3 \mathrm{COONa}$

Solution:
Because it is a salt of strong base with a weak acid.

Topic: Chemistry, Ionic Equilibrium, JEE Main
Which of the following secretes luteinizing hormone?

Options:
A Adenohypophysis
B Corpus luteum
C Neurohypophysis
D Pars nervosa

The correct answer is:
Adenohypophysis

Solution:
Basophil cells of pars distalis or anterior pituitary (adenohypophysis) secrete a luteinizing hormone which is responsible for maintenance of corpus luteum.

Topic: Biology, Chemical Coordination and Integration, NEET
Which of the following semi-conducting devices is used as voltage regulator?

Options:
A Photo diode
B LASER diode
C Zener diode
D Solar cell

The correct answer is:
Zener diode

Solution:
Voltage regulator is an electronic circuit that provides stabledc voltage independent of load current, temperature and ac
line voltage variations. Zener-diode is used as a voltage regulator.

Topic: Physics, Kinetic Theory of Gases, JEE Main