55. A thin prism of angle 15° made of glass of refractive index $μ_1$ = 1.5 is combined with another prism of glass of refractive index $μ_2$ = 1.75. The combination of the prism produces dispersion without deviation. The angle of the second prism should be ?

44. A biconvex lens has a radius of curvature of magnitude 20 cm. Which one of the following options best describe the image formed of an object of height 2 cm placed 30 cm from the lens?

43. A converging beam of rays is incident on a diverging lens. Having passed through the lens the rays intersect at a point 15 cm from the lens on the opposite side. If the lens is removed the point where the rays meet will move 5 cm closer to the lens. The focal length of the lens is ?

24. Which of the following is not due to total internal reflection ?

A parallel plate capacitor has a uniform electric field E in the space between the plates. If the distance between the plates is d and area of each plate is A, the energy stored in the capacitor is ?

Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides BC, AC and AB, D and E are the mid points of BC and CA. The work done in taking a charge Q from D to E is ?

Four electric charges +q, +q, −q and −q are placed at the corners of a square of side 2 L (see figure). The electric potential at point A, midway between the two charges +q and +q, is ?

The electric potential V at any point (x, y, z), all in meters in space is given by V = 4x2 volt. The electric field at the point (1, 0, 2) in volt/ meter is ?

A charge Q is enclosed by a Gaussian spherical surface of radius R. If the radius is doubled, then the outward electric flux will ?