If emissivity of bodies X and Y are e_x and e_y and absorptive power are A_x and A_y then

An ideal black body at room temperature is thrown into a furnace. It is observed that

Three rods made of the same material and having the same cross-section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at 0°C and 90°C respectively. The temperature of the junction of the three rods will be

The plots of intensity versus wavelength for three black bodies at temperature T₁, T₂ and T₃ respectively are as shown. Their temperatures are such that

Three identical point charges, as shown are placed at the vertices of an isosceles right angled triangle. Which of the numbered vectors coincides in direction with the electric field at the mid-point M of the hypotenuse

Two identical conductors of copper and aluminium are placed in an identical electric fields. The magnitude of induced charge in the aluminium will be

Four charges are arranged at the corners of a square ABCD. as shown in the adjoining figure. The force on the charge kept at the centre O is

There is an electric field E in X-direction. If the work done on moving a charge 0.2 C through a distance of 2 m along a line making an angle 60° with the X-axis is 4.0, what is the value of E.

As shown in the fig. charges +q and –q are placed at the vertices B and C of an isosceles triangle. The potential at the vertex A is

A tin nucleus has charge +50e. If the proton is at a distance 10^–12m from the nucleus, then the potential V at this position is [charge on the proton = 1.6×10^–19C]

An electron which is initially at rest is accelerated through a potential difference of one volt. The energy acquired by the electron is

A charge q is placed at the centre of the open end of a cylindrical vessel. The flux of the electric field through the surface of the vessel is

Fig. shows a distribution of charges. The flux of electric field due to these charges through the surface S is

As per fig. a point charge +q is placed at the origin O. Work done in taking another point charge –Q from the point A [Co-ordinates (0,a)] to another point B [Co-ordinates (a, 0)] along the straight path AB is :

Three point charges are placed at the corners of an equilateral triangle. Assuming only electrostatic forces are acting.

Let be a cube root of unity and be the set of all non‐singular matrices of the form , where each of a, b and is either Then the number of distinct matrices in the set is‐

Hence no of matrices formed = 2