1 amp. current flow is a circuit when a cell is connected to 1 ohm resistance and 0.5 amp. to a 3 ohm resistance. The internal resistance of cell is :

(1) 2 ohm

(2) 1.0 ohm

(3) 1.5 ohm

(4) 0.5 ohm

 A ball of mass m attached to the end of a string revolves in a vertical circle of radius R. When the ball is at the top of the circle it is moving horizontally with a speed v. What is the tension in the string when the ball is at the top of the circle?

1) (mv² / R) -mg

2) mv²/ R

3) 0

4) mg

If the kinetic energy of the particle is increased to 1616 times previous the percentage change in the deBrogille wavelength of the particle is  

1) 25 %
2) 62 %
3) 75 %
4) 50 %

A physical parameter a can be determined by measuring the parameters b, c, d and e using the relation a = b^α c^β / d^γ e^δ. If the maximum errors in the measurement of b, c,d and e are b₁%, c₁%, d₁% and e₁ %, then the maximum error in the value of a determined by the experiment is

1) (b₁ + c₁ + d₁ + e₁)%
2) (b₁ + c₁ – d₁ – e₁)%
3) (αb₁ + βc₁ – γd₁ – δe₁)%
4) (αb₁ + βc₁ + γd₁ + δe₁)%

If the ratio of amplitude of two superposed waves is 2:1, then the ratio of maximum intensity and minimum intensity is

1) 9:1
2) 1:9
3) 4:1
4) 1:4

When a capillary tube is dipped in a liquid, the liquid rises to a height h in the tube. The free liquid surface inside the tube is hemispherical in the shape. The tube is now pushed down so that the height of the tube outside the liquid is less than h

1) The liquid will come out of the tube like in a small fountain.
2) The liquid will ooze out of the tube slowly.
3) The liquid will fill the tube but not come out of its upper end
4) The free liquid surface inside the tube will not be hemispherical.

A glass of refractive index 1.5 is coated with a thin layer of thickness of tt of refractive index 1.8 light of wavelength λ tavelling at the upper and the lower surfaes of the layer and the two reflected rays interfere. If λ=648nm , obtain the least value of tt (in 10⁻⁸m) for which the rays interfere constructively.

1) 1.8 ×10⁻⁸m

2) 0.9 ×10⁻⁸m

3) 9×10⁻⁸m

4) 18×10⁻⁸m

The power of a sound from the speaker of a radio is 20 mW. By turning the knob of the volume control, the power of the sound is increased to 400 mW. The power increase in decibels as compared to the original power is

(1)     13.0 dB                          (2)     10 dB

(3)     20 dB                             (4)     8000 dB

A black body at high temp T K, radiates energy E. The temperature now fallen to T/ 2 K,the final radiated energy will be : 

1) $$\dfrac{E}{4}$$
2) $$\dfrac{E}{2}$$
3) $$2E$$
4) $$\dfrac{E}{16}$$

An ideal transformer steps down 220 V to 22 V in order to operate a device with an impedance of 220 W. The current in the primary is:

1) 0.01 A
2) 0.1 A
3) 1 A
4) 10 A