A mercury barometer is defective. When an accurate barometer reads `770` mn, the defective one reads
Channel: Doubtnut
Date: 2020-02-16

A mercury barometer is defective. When an accurate barometer reads `770` mn, the defective one reads `760` mn. When the accurate one reads `750` mn, the defective one reads `742` mn. Then The length of air coloumn when accurate barometer reads `770`mm isn.