Physics Test - ...

Two spherical bodies A (radius 6 cm ) and B(radius 18 cm ) are at temperature T1 and T2, respectively. The maximum intensity in the emission spectrum of A is at 500 nm and in that of B is at 1500 nm. Considering them to be black bodies, what will be the ratio of the rate of total energy radiated by A to that of B?

A thin uniform annular disc (see figure) of mass M has outer radius 4R and inner radius3R. The work required to take a unit mass from point P on its axis to infinity is

A metal rod of length ‘L’ and mass ‘m’ is pivoted at one end. A thin disk of mass ‘M’ and radius ‘R’ (

Incandescent bulbs are designed by keeping in mind that the resistance of their filament increases with theincrease in temperature. If at room temperature, 100 W, 60 W and 40 W bulbs have filament resistances R100, R60 and R40, respectively, the relation between these resistances is

A silver sphere of radius 1 cm and work function 4.7 eV is suspended from an insulating thread in freespace. It is under continuous illumination of 200 nm wavelength light. As photoelectrons are emitted, the sphere gets charged and acquires a potential. The maximum number of photoelectrons emitted from the sphere is A × 10^z (where 1 < A < 10). The value of ‘Z’ is

A stationary source is emitting sound at a fixed frequency f0, which is reflected by two cars approaching the source. The difference between the frequencies of sound reflected from the cars is 1.2% of f0. What is the difference in the speeds of the cars (in km per hour) to the nearest integer ? The cars are moving at constant speeds much smaller than the speed of sound which is 330 ms^-1.

Water (with refractive index = 4/3) in a tank is 18 cm deep. Oil of refractive index 7/4 lies on water making a convex surface of radius of curvature ‘R = 6 cm’ as shown. Consider oil to act as a thin lens. An object ‘S’ is placed 24 cm above water surface. The location of its imageis at ‘x’ cm above the bottom of the tank. Then ‘x’ is

When a particle of mass m moves on the x-axis in a potential of the form V(x) = kx^2 it performs simple harmonic motion. The corresponding time period is proportional to √(m/k) , as can be seen easily using dimensional analysis. However, the motion of a particle can be periodic even when its potential energy increases on both sides of x = 0 in a way differentfrom kx^2 and its total energy is such that the particle does not escape to infinity. Consider a particle of mass m moving on the x-axis. Its potential energy is V(x) = αx^4 (α > 0) for |x|near the origin and becomes a constant equal to V0 for |x| ≥ X0 (see figure). Que :If the total energy of the particle is E, it will perform periodic motion only if

A piece of ice (heat capacity = 2100 J kg^-1 °C^-1 and latent heat = 3.36 ×10^5 J kg^-1) of mass m grams is at -5°C at atmospheric pressure. It is given 420 J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1 gm of ice has melted. Assuming there is no other heat exchange in the process, the value of m is

Which of the following statement(s) is/are correct?