Physics Test - ...

Two charges, each equal to q, are kept at x=a on the x-axis. A particle of mass m and charge q =q/2 is placed at the origin. If charge q is given a small displacement (y << a) along the y-axis, the net force acting on the particle is proportional to:

The I – V characteristic of an LED is

A charge Q is uniformly distributed over a long rod AB of length L as shown in the figure. The electric potential at the point O lying at a distance L from the end A is:

The amplitude of a damped oscillator decreases to 0.9 times its original magnitude is 5s. In another 10s it will decrease to α times its original magnitude, where α equals.

A projectile is given an initial velocity of (i + 2j) m/s, where i is along the ground and j is along the vertical. If g = 10 m/s² , the equation of its trajectory is:

Two coherent point sources S₁ and S₂ are separated by a small distance ‘d’ as shown. The fringes obtained on the screen will be:

Let [ε0] denote the dimensional formula of the permittivity of vacuum. If M = mass, L = length, T = time and A = electric current, then:

The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows:

A beam of unpolarised light of intensity I₀ is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45° relative to that of A. The intensity of the emergent light is:

A hoop of radius r and mass m rotating with an angular velocity ω₀ is placed on a rough horizontal surface. The initial velocity of the centre of the hoop is zero. What will be the velocity of the centre of the hoop when it ceases to slip?