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In the microwave oven, we use electromagnetic oscillators which produce electromagnetic waves in the wavelength range

1) 1mm to 10m 2) 0.7 μm to 1mm 3) 0.1 m to 1mm 4) 0.1 μm to 0.7 μm... View Article

Our eyes respond to wavelength ranging from

1) 400nm to 700nm 2) -∞ to +∞ 3) 1mm to 700nm 4) 700nm to 800nm Answer: 1) 400nm to 700nm... View Article

What is the ratio of velocities of light rays of wavelengths 4000^oA and 8000^oA in vacuum?

1) 1 : 2 2) 1 : 1 3) 2 : 1 4) cannot be determined Answer:2) 1 : 1... View Article

Unit of energy density of electromagnetic wave is _____________

1) Jm-3 2) Jm-2 3) Wm-2 4) None of these Answer: 1) Jm-3 Solution: Energy density = Energy/Volume = J/m3 = Jm-3

The frequency of electromagnetic wave having wavelength 25mm is ____________ Hz

1) 1.2 x 1010 2) 7.5 x 105 3) 1.2 x 108 4) 7.5 x 106 Answer: 1) 1.2 x 1010Hz... View Article

Which of the following electromagnetic waves is used in telecommunication?

1) radio waves 2) visible radiations 3) ultraviolet rays 4) microwaves Answer: 4) microwaves Solution: Microwaves are used in telecommunication

Which of the following electromagnetic waves has the longest wavelength?

1) Radio waves 2) Infrared radiations 3) x rays 4) visible rays Answer: Radio waves Solution: Radio waves have the... View Article

In the electromagnetic spectrum, the visible light lies between

1) radiowaves and microwaves 2) ultraviolet rays and infrared rays 3) ultraviolet rays and x rays 4) infrared rays and... View Article

What is the wavelength of the range of electromagnetic waves?

1) 10-8 m to 1015 m 2) 10-15 m to 108 m 3) 10-15 m to 1015 m 4) 108... View Article

Electromagnetic waves used in medicine to destroy cancer cells

1) radio waves 2) infrared rays 3) gamma rays 4) ultraviolet rays Answer: 3) gamma rays Solution: Gamma rays are used... View Article

An observer is at 2m from an isotropic point source of light emitting 40w power. The RMS value of electric due to the source at the position of the observer is_________

1) 5.77 x 10-8 Vm-1 2) 17.3 Vm-1 3) 57.7 x 10-8 Vm-1 4) 1.73 Vm-1 Answer: 2) 17.3 Vm-1 Solution: Intensity = power/4πr2 =... View Article

Electromagnetic waves travelling in a medium which has relative permeability 1.3 and relative permeability 2.14 speed of electromagnetic waves in this medium will be _________

1) 3.6 x 108 m/s 2) 1.8 x 108 m/s 3) 1.8 x 106 m/s 4) 13.6 x 106 m/s Answer: 2) 1.8 x 108 m/s Solution: Speed of... View Article

An electric charge oscillating with a frequency of 1kilo cycles/s can radiate electromagnetic waves of wavelength

1) 100km 2) 200km 3) 300km 4) 400km Answer: 3) 300km Solution: f = 1kilo cycles/s = 1 x 103 cycles/s = 103... View Article

If a source is transmitting an electromagnetic wave of frequency 8.2 × 10⁶ Hz, then the wavelength of the electro-magnetic waves transmitted from the source will be

1) 36.6 m 2) 40.5 m 3) 42.3 m 4) 50.9 m Answer: 1) 36.6 m Solution: Wavelength, λ = c/ν =... View Article

A plane electromagnetic wave of frequency 20 MHz travels through space along the x-direction. If the electric field vector at a certain point in space is 6 Vm^-1, what is the magnetic field vector at that point?

1) 2 x 10-8 T 2) (1/2) x 10-8 T 3) 2 T 4) (1/2) T Answer: 1) 2 x 10-8 T Solution:... View Article

The maximum electric field in a plane electromagnetic wave is 900NC^–1. The wave is going in the x-direction and the electric field is in the y-direction. The maximum magnetic field in the wave is _____________T.

1) 3 x 10-8 2) 3 x 10-6 3) 27 x 10-6 4) 27 x 1010 Answer: 2) 3 x 10-6... View Article

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