# A charged particle travels along a straight line with a speed v in a region where both electric foeld E and magnetic field B are present. If follows that   1.  |E| = v |B| and two fields are parallel   2.  |E| = v |B| and two fields are perpendicular   3.  |B| = v |E| and two fields are parallel   4.  |B| = v |E| and two fields are perpendicular

What will be the wave velocity, if the radar gives 54 waves/min and wavelength of the given wave is 10 m?

1.  4 m/s

A transformer of 100% efficiency has 200 turns in the primary coil and 40000 turns in secondary coil. It is connected to a 220 V main supply and secondary feeds to a 100 kΩ resistance. The potential difference per turn is

1.  1.1 V

2.  25 V

3.  18 V

4.  11 V
Subtopic:  Transformer |
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A thin convex lens of refractive index 1.5 has 20 cm focal length in air. If the lens is completely immersed in a liquid of refractive index 1.6, its focal length will be

1.  -160 cm

2.  - 100 cm

3.  + 10 cm

4.  +100 cm
Subtopic:  Lens Makers' Formula |
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SI unit of permittivity is

1.  C2m2N2

2.  C2m-2N-1

3.  C2m2N-1

4.  C-1m2N-2

Subtopic:  Coulomb's Law |
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A spherical drop of capacitance 1μF is broken into eight drops of equal radius. Then, the capacitance of each small drop is
1.   μF
2.   μF
3.   μF
4.  8 μF
Subtopic:  Capacitance |
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A simple harmonic oscillator consists of a particle of mass m, and an ideal spring with spring constantk. The particle oscillates with a time period T. The spring is cut into two equal parts, Of one part oscillates with the same particles, the time period will

1.  2T

The coefficient of viscosity for hot air is

1.  greater than the coefficient of viscosity for cold air

2.  smaller than the coefficient of viscosity for cold air

3.  same than the coefficient of viscosity for cold air

4.  increase than the coefficient of viscosity for cold air

Subtopic:  Viscosity |
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An artificial satellite moving in a circular orbit around the earth has a total (kinetic + potential) energyE0. Its potential energy is
1.  -E0

Subtopic:  Satellite |
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A thin hollow sphere of mass m is completely filled with a liquid of mass m. When the sphere rolls with a velocity v, kinetic energy of the system is (neglect friction)

1.  mv2