# The half life of radioactive elements is 600 yr the fraction of sample that would remain after 3000 yr is   1.  1/2   2.  1/16   3.  1/8   4.  1/32

A particle moves along with x-axis. The position x os particles with respect to time t from origin given by x = b0 + b1t + b2t2. The acceletration of particle is

1.  b0

Root mean square speed of the molecules of ideal gas is v. If pressure is increased two times at constant temperature, then the rms speed will become

1.

1 mol of gas occupies a volume of 200 mL at 100 mm pressure. What is the volume occupied by two moles of gas at 400 mm pressure and at same temperature?

1.  50 mL

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

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 |
55%
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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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