The intensity of visible radiation at a distance of 1 m from a bulb of 100 W which converts only 5% of its power into light, is:
1. 0.4 W/m2
2. 0.5 W/m2
3. 0.1 W/m2
4. 0.01 W/m2
On an EM wave, the amplitude of electric and magnetic fields are 100 v/m and 0.265 A/m. The maximum energy flow is
(1) 26.5 (2) 46.7
(3) 66.5 (4) 86.5
The most penetrating radiation out of the following is:
(1) X-rays (2) -rays (3) -rays (4) -rays
Which of the following statements about electromagnetic waves is/are correct:
A. | X-rays in vacuum travel faster than light waves in vacuum. |
B. | The energy of an X-ray photon is greater than that of a light photon. |
C. | Light can be polarised but X-ray cannot. |
1. A and B
2. B and C
3. A, B and C
4. B only
The magnetic field in a plane EM wave traveling in the positive x-direction is given by
The equation for electric field is :
1. E=100sin [(2(t-x/c)]
2. E=(3)sin [(2(t-x/c)]
3. E=3sin [(2(t-x/c)]
4. E=100sin [(2(t-x/c)]
Statement I: A changing electric field produces a magnetic field.
Statement II: A changing magnetic field produces an electric field.
(1) If both statement-I and Statement-II are true, and Statement-II is the correct explanation of Statement-I.
(2) If both Statement-I and Statement-II are true but Statement-II is not the correct explanation of Statement-I.
(3) If Statement-I is true but Statement-II is false.
(4) If Statement-I is false but Statement-II is true.
Statement-I: Gamma rays are more energetic than X-rays.
Statement-II: Gamma rays are of nuclear origin but X-rays are produced due to sudden deceleration of high energy electrons while falling on a metal of high atomic number.
(1) If both statement-I and Statement-II are true, and Statement-II is the correct explanation of Statement-I.
(2) If both Statement-I and Statement-II are true but Statement-II is not the correct explanation of Statement-I.
(3) If Statement-I is true but Statement-II is false.
(4) If Statement-I is false but Statement-II is true.
The S.I. unit of displacement current is:
1. Henry
2. Coulomb
3. Ampere
4. Farad
The relation between electric field E and magnetic field intensity H in an electromagnetic wave is:
(1) E = H
(2)
(3)
(4)
An electromagnetic wave going through Vaccum is described by
(1)
(2)
(3)
(4) none of these