Free Printable 8. Electro Magnetic Waves

1.

Which of the following has/have zero average value in a plane electromagnetic wave?

a)

Both Magnetic and Electric Fields

b)

Electric Field only

c)

Magnetic Field only

d)

None of these

2.

The electric field of an electromagnetic wave travelling through vacuum is given by the equation E = E₀ sin $\left(kx-\omega t\right)$ . The quantity that is independent of wavelength is

a)

$k\omega$

b)

$\frac{k}{\omega}$

c)

$k^2w$

d)

$\omega$

3.

The amplitude of the magnetic field of a harmonic electromagnetic wave in vacuum is B₀ = 510 nT. The amplitude of the electric field part of the wave is

a)

120 NC^-1

b)

134 NC^-1

c)

510 NC^-1

d)

153 NC^-1

4.

Radiations of intensity 0.5 W m^–2 are striking a metal plate. The pressure on the plate is

a)

0.166 X 10^-8 N m^-2

b)

0.332 X 10^-8 N m^-2

c)

0.111 X 10^-8 N m^-2

d)

0.083 X 10^-8 N m^-2

5.

The dimensions of $\left(\mu_0\epsilon_0\right)^{\frac{1}{2}}$ are

a)

$\left[L^{\frac{1}{2}}T^{\frac{-1}{2}}\right]$

b)

$\left[L^{-1}T\right]$

c)

$\left[L^{ }T^{-1}\right]$

d)

$\left[L^{\frac{-1}{2}}T^{\frac{1}{2}}\right]$

6.

Molybdenum is used as a target element for the production of X-rays because it is

a)

light and can easily deflect electrons

b)

light and can absorb electrons

c)

a heavy element with a high melting point

d)

an element having high thermal conductivity

7.

The electric field part of an electromagnetic wave in a medium is represented by E_x = 0; E_y = $2.5\ NC^{-1}\ \times\cos\left[\left(2\pi\times10^6\ rad\ s^{-1}\right)t-\left(\pi\times10^{-2}rad\ m^{-1}\right)x\right]$ ; Ez = 0. The wave is

a)

moving along the x direction with frequency 10⁶ Hz and wavelength 100 m

b)

moving along x direction with frequency 10⁶ Hz and wavelength 200 m

c)

moving along –x direction with frequency 10⁶ Hz and wavelength 200 m

d)

moving along y direction with frequency 2pi × 10⁶ Hz and wavelength 200 m.

8.

The amplitude of magnetic field in a parallel beam of light of intensity 2.0 W m^–2 is

a)

1.3 x 10^-7 T

b)

1.3 x 10^-6 T

c)

1.3 x 10^-5 T

d)

1.3 x 10^-8 T

9.

Light with an energy flux of 18 W cm^–2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 20 cm², the total momentum delivered to the surface during a span of 30 minutes is

a)

2.16 x 10^-3 kg ms^-1

b)

2.16 x 10^-4 kg ms^-1

c)

4.32 x 10^-3 kg ms^-1

d)

4.32 x 10^-4 kg ms^-1

10.

An earth orbiting satellite has solar energy collecting panel with total area 5 m². If solar radiations are perpendicular and completely absorbed, the average force associated with the radiation pressure is (solar constant = 1.4 kW m^–2).

a)

2.33 x 10^-3 N

b)

2.33 x 10^-4 N

c)

2.33 x 10^-5 N

d)

2.33 x 10^-6 N

8. Electro Magnetic Waves

Total questions: 10

Worksheet time: 50mins

Similar Resources on Wayground