Question

The weight of a body at earth's surface is W. At a depth half way to the centre of the earth, it will be (assuming uniform density in earth) –

• A. W
• B. W/2
• C. W/4
• D. W/8

Answer 1

Answer: (B)

W/2

Answer 2

Due to depth g' = g $\left\{ 1 - \frac { \mathrm { d } } { \mathrm { R } _ { \mathrm { e } } } \right\}$Q d = R_e/2

so g' = g $\left\{ 1 - \frac { \mathrm { R } _ { \mathrm { e } } / 2 } { \mathrm { R } _ { \mathrm { e } } } \right\}$= g/2

Now g' is half so weight is also half.