Question

A box, when hung from a spring balance shows a reading of $50$kg. If the same box is hung from the same spring balance inside an evacuated chamber, the reading on the scale will be.

• A. $50$kg because the mass of the box remains unchanged
• B. $50$kg because the effect of the absence of the atmosphere will be identical on the box and the spring balance
• C. Less than $50$kg because the weight of the column of air on the box will be absent
• D. More than $50$kg because the atmospheric buoyancy force will be absent

Answer 1

The correct option is D More than $50$kg because the atmospheric buoyancy force will be absent

In an evacuated chamber, in absence of air, buoyancy force due to air on box is absent, so the reading will be more than 50 kg .