Electromagnetic Waves — Physics STD 12 Science — Question

Two periodic waves of amplitudes A₁ and A₂ pass through a region. If A₁ > A₂, the difference in the maximum and minimum resultant amplitude possible is:

1. 2A₁
2. 2A₂
3. A₁ + A₂
4. A₁ - A₂

Energy required for the electron excitation in Li++ from the first to the third Bohr orbit is:

A charge "Q" and "2Q" are 0.05 meters apart and isolated. The ratio of the electrostatic force on the charge Q to the force on charge 2Q is:

A wavefront presents one, two and three HPZ at points A, B and C respectively. If the ratio of consecutive amplitudes of HPZ is 4 : 3, then the ratio of resultant intensities at these point will be

(a) 169 : 16  : 256

(b) 256 : 16 : 169

(c) 256 : 16 : 196

(d) 256 : 196 : 16

Which of the following quantities do not depend on the choice of zero potential or zero potential energy?

The device that does not work on the principle of mutual induction is

(a) Induction coil

(b) Motor

(c) Tesla coil

(d) Transformer

Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called:

For a given material, the energy and wavelength of characteristic X-rays satisfy:

The expression for the capacity of the capacitor formed by compound dielectric placed between the plates of a parallel plate capacitor as shown in figure, will be (area of plate = A)

(a)

(b)

(c)

(d)

In Huygens' theory, the plane of particles vibrating in the same state is called: