Step 1: Use the formula for weight at depth.- Weight on surface: W = mg = 400N.- At depth d = R/2,
Step 2: Substitute the values.
W' = W(1 - dR)
W' = 400(1 - R/2R)
W' = 400(1 - 12)
W' = 400 $\cdot$ 12 = 200N
Final Answer: Weight at half the earth’s radius = 200N
Young double slit arrangement is placed in a liquid medium of 1.2 refractive index. Distance between the slits and screen is 2.4 m.
Slit separation is 1 mm. The wavelength of incident light is 5893 Å. The fringe width is:

Gravitational force is a central force that depends only on the position of the test mass from the source mass and always acts along the line joining the centers of the two masses.
According to Newton’s law of gravitation, “Every particle in the universe attracts every other particle with a force whose magnitude is,
By combining equations (1) and (2) we get,
F ∝ M1M2/r2
F = G × [M1M2]/r2 . . . . (7)
Or, f(r) = GM1M2/r2 [f(r)is a variable, Non-contact, and conservative force]