Physics Test - ...

β-decay

 

The energy of a system as a function of time t is given as E(t) = A^2 exp(-αt), where α = 0.2 s^-1. The measurement of A has an error of 1.25 %. If the error in the measurement of time is 1.50 %, the percentage error in the value of E(t) at t = 5 s is

Consider a concave mirror and a convex lens (refractive index = 1.5) of focal length 10 cm each, separated by a distance of 50 cm in air (refractive index = 1) as shown in the figure. An object is placed at a distance of 15 cm from the mirror. Its erect image formed by this combination has magnification M1. When the set- up is kept in a medium of refractive index 7/6, the magnification becomes M2. The magnitude | M2/M1 | is

Four harmonic waves of equal frequencies and equal intensities I0 have phase angles 0, π/3, 2π/3 and π. When they are superposed, the intensity of the resulting wave is nI0. The value of n is

A body is projected vertically upwards. The times corresponding to height h while ascending and while descending are t1 and t2 respectively. Then the velocity of projection is (g is acceleration due to gravity)

The figures below depict two situations in which two infinitely long static line charges of constant positive line charge density λ are kept parallel to each other. In their resulting electric field, point charges q and -q are kept in equilibrium between them. The point charges are confined to move in the x direction only. If they are given a small displacement about their equilibrium positions, then the correct statement(s) is(are)