Question

A barometer kept in an elevator reads 76 cm when the elevator is accelerating

Answer 1

under normal conditions when elevator is accelerated upward the barometer reads value less than 76cm by ACC. to que it reads 76cm means the air is applying more pressure to lift the liquid upto the height of 76 cm. so air is applying more pressure than normal pressure 76cm.

Answer 2

Acc. to question the pressure is 76 cm means that the air is applying more pressure to lift the liquid to a height of 76cm.so the air pressure in the lift is higher than the normal(76 cm).

the liquid becomes heavier m*(g+a) when the lift accelerating upwards. so it requires more more pressure from the air onto the liquid to rise at the height of 76 cm.