Q.1.
A new system of unit is evolved in which the values of µ0 and εo are 2 and 8 respectively. Then the speed of light in this system will be
-
33%
a)0.25
-
50%
b)0.5
-
0%
c)0.75
-
17%
d)1
Q.2.
Our eyes respond to wavelength ranging from
-
50%
a) 400nm to 700nm
-
17%
b) 1mm to 700nm
-
0%
c)-∞ to +∞
-
33%
d)700nm to 800nm
Q.3.
In microwave oven, we use electromagnetic oscillators which produce electromagneticwaves in the wavelength range
-
33%
a) 1mm to 10m
-
50%
b) 0.7µmto 1mm
-
17%
c)0.1m to 1mm
-
0%
d)0.1µmto 0.7µm
Q.4.
A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% effecient in converting electrical power to electromagnetic waves and consumes 100W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 5m from the lamp will be
-
60%
a) 1.34 V/m
-
20%
b) 2.68 V/m
-
0%
c)4.02 V/m
-
20%
d)5.36 V/m
Explanation
Q.5.
The Sun radiates electromagentic energy at the rate of 3.9×1026 W. Its radius is 6.96×108 m . The intensity of sun light ( in W/m2) at the solar surface will be
-
0%
a) 5.6×106
-
75%
b) 5.6×107
-
25%
c) 4.2×106
-
0%
d) 4.2×107
Q.6.
An electromagnetic wave of frequency ν=3.0 Mhz passes from vacuum into a dielectric medium with permitivity ε=4.Then [ AIEEE 2004]
-
25%
a)Wavelength is doubled and frequency remains unchaged
-
25%
b) Wvaelength is doubled and frequency becopmes half
-
50%
c)wavelength is doubled and frequency becomes half
-
0%
d)wave length and frequency both remains unchaged
Q.7.
The electrical conductive it of earth's atmosphere increases with altitude because of [ Bihar CECE 2004]
-
25%
a) reflection of atmospheres
-
50%
b) accelerated protons
-
25%
c)measure of voltagae
-
0%
d)measure of charge
Q.8.
If the wavelength of light is 4000 Å then the number of waves in 1mm length will be [ JKCET 2004]
-
25%
a) 25
-
0%
b) 0.25
-
75%
c)0.25×104
-
0%
d)2.5×104
Q.9.
Sodium lamps are used in foggy conditions because
-
25%
a) yellow light is scatered less by the fog particles
-
0%
b) yellow light is scattered more by the fog particles
-
25%
c) yellow light is unaffected during its passage through the fog
-
50%
d) wavelength of yellow light is the mean of visible part of the sprectrum
Q.10.
The rms value of electric field of the radiation coming from sun is 720 N/C, The average radiation density in J/m3 is ..
-
0%
a)81.35 × 10-12
-
25%
b) 3.3 × 10-3
-
50%
c)4.58 × 10-6
-
25%
d)6.37 × 10-9
Q.11.
In the region closer to the oscillating charges, the phase difference between E and B fields is ... and their magnitude quickly decreases as ... with distance r from the source
-
0%
a) 0, r-1
-
25%
b) π/2, r-3
-
75%
c)π/2, r-1
-
0%
d)0, r-3
Q.12.
At room temperature, if the relative permittivity of water be 80 and the relative permeability be 0.0222, then the velocity of light in water is ... m/s
-
0%
a)3×108
-
25%
b) 2.5×108
-
75%
c)2.25×108
-
0%
d)3.5 ×108
Q.13.
If the electric field asssociated with a radiation of frequency 10 MHz is E=10sin( kx -ωt) mV/m . then its energy density in J/m3 is [ εo=8.85×10-12C2N-1m-2]
-
25%
a) 4.425×10-16
-
25%
b) 6.26×10-14
-
25%
c) 8.85×10-16
-
25%
d) 8.85×10-14
Q.14.
In hertz's experiment the .... of the electromagnetic waves is equal to the kinetic energy of the charges oscillating between the two spheres
-
0%
a)frequency
-
25%
b) energy
-
25%
c)wavelength
-
50%
d)velocity
Q.15.
The etensity of plane electromagnetic wave with Bo=1.0×10-4T in W/m2 is ..
-
25%
a) 2.38×106
-
25%
b) 1.19×106
-
0%
c)6×105
-
50%
d)4.76×106
Q.16.
The magnetic field of an electromagnetic plane travelling along the negative X-direction is given by By=2×10-7 sin(0.5×103 x + 1.5×1011 t ) T what is the wavelength and frequecy of the wave
-
25%
a) 1.26 m, 23.9 Hz
-
25%
b) 2.56 cm, 12.0 GHz
-
25%
c)3.21 m , 36.2 GHz
-
25%
d)1.26 cm, 23.9 GHz
Q.17.
For a radiation of 6 GHz passing through air, the wave number ( number of waves) per 1 m length is ...(1 GhZ=109 Hz)
-
0%
a) 3
-
25%
b) 5
-
50%
c) 20
-
25%
d) 30
Q.18.
The power in a two-wire transmission line travels
-
25%
a)inside the conductors
-
50%
b) outside the conductors
-
0%
c)none of the above
-
25%
d)both inside and outside the conductors
Q.19.
The characteristic impedance of a lossless transmission line is given by
-
25%
a) Zo=√LC
-
50%
b) Zo=√ (L/C)
-
0%
c)Zo=√(C/L)
-
25%
d)Zo=LC
Q.20.
An 'antenna' is
-
25%
a) inductive
-
25%
b) capacittative
-
25%
c)resistive above its resonance frequency
-
25%
d)none of the above
Q.21.
A laser is a coherent source because it contains
-
50%
a) many wavelengths
-
0%
b) uncoordinated wave of a particular wavelength
-
0%
c) coordinated wave of many wavelengths
-
50%
d) coordinated waves of a particular wavelength
Q.22.
A modulating signal of frequency 5kHz and peak voltage of 6V is used to modulate a carrier of frequency 10 MHz and peak votage of 10V. what is modulation index
-
25%
a)1.66
-
50%
b) 0.6
-
25%
c)2
-
0%
d)0.5
Q.23.
In above problem (Q161) what is Low side band frequency (LSB)
-
25%
a) 10.005 MHz
-
25%
b) 0.05 MHz
-
0%
c)22 MHz
-
50%
d)9.995 Mhz
Q.24.
In problem Q161 What is upper side band frequency (USB)
-
50%
a)10.005 MHz
-
0%
b)0.05 MHz
-
25%
c)22 MHz
-
25%
d)9.995 MHz
Q.25.
In problem Q161 what is the amplitude of LSB and USB
-
25%
a) 3V, 6V
-
0%
b) 6V, 3V
-
50%
c) 3V , 3V
-
25%
d) 6V, 6V
Q.26.
Who produced the electromagnetic waves first ?
-
0%
a)Marconi
-
0%
b)Maxwell
-
0%
c)J.C. Bose
-
100%
d)Hertz
Q.27.
A plane electromagnetic wave is incident on a material surface. The wave delivers momentum P and energy E
-
0%
a) P=0, E ≠ 0
-
0%
b)P ≠ 0, E=0
-
100%
c)P ≠ 0, E ≠ 0
-
0%
d) P=0, E=0
Q.28.
If Vγ Vx and Vm are the velocity of the γ rays, x rays, micro waves respectively inspace, then
-
25%
a)Vγ < Vx < Vm
-
50%
b) Vγ=Vx=Vm
-
25%
c)Vγ > Vx > Vm
-
0%
d)Vγ > Vx < Vm
Q.29.
If λγ ,λx and λm are the wave lengths of the γ rays, x rays and micro waves respectivelyin space then
-
0%
a) λγ > λx > λm
-
25%
b) λγ < λx < λm
-
75%
c) λγ=λx=λm
-
0%
d) λγ >λm > λx
Q.30.
According to Maxwell, a changing electric field produces
-
0%
a)emf
-
25%
b) Electric current
-
50%
c)magnetic field
-
25%
d)radiation pressure