Question

In Guericke’s experiment to show the effect of atmospheric pressure, two copper hemispheres were tightly fitted to each other to form a hollow sphere and the air from the sphere was pumped out to create vacuum inside. If the radius of each hemisphere is $R$ and the atmospheric pressure is $p$, then the minimum force required (when the two hemispheres are pulled apart by the same force) to separate the hemispheres is

• A. $2p\pi R^2$
• B. $4p\pi R^2$
• C. $p\pi R^2$
• D. $\frac{p}{2}\pi R^2$

Answer 1

Answer: (C)

In Guericke’s experiment,

If pressure difference between outside and inside is $p$, then
$\frac{F}{A}=p$ or $F=pA=p\pi R^2$