Electromagnetic Waves — Physics STD 12 Science — Question

In a transformer, the coefficient of mutual inductance between the primary and the secondary coil is 0.2 henry. When the current changes by 5 ampere/second in the primary, the induced e.m.f. in the secondary will be

(a)  5 V

(b) 1 V

(c)  25 V

(d) 10 V

Two plane mirrors. A and B are aligned parallel to each other, as shown in the figure. A light ray is incident at an angle of 30°  at a point just inside one end of A. The plane of incidence coincides with the plane of the figure. The maximum number of times the ray undergoes reflections (including the first one) before it emerges out is

(a) 28

(b) 30

(c) 32

(d) 34

When a dielectric slab is introduced between the two plates of condenser then its capacity ___________.

The binding energy per nucleon in a nucleus shows:

Unit of electromotive force :

When no current is passed through a conductor:

Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio:

An electromagnetic field exists only when there is.

Two wires of equal diameters, of resistivities  and   and lengths l₁ and l₂, respectively, are joined in series.  The equivalent resistivity of the combination is

(a)

(b)

(c)

(d)