Current Electricity — Physics STD 12 Science — Question

Which of the following statements is correct?

Water is flowing in streamliries motion through a tube with its axis horizontal Consider two points A and B in the tube at the same horizontal level:

1. The pressures at A and B are equal for any shape of the tube.
2. The pressures are never equal.
3. The pressures are equal if the tube has a uniform cross section.
4. The pressures may be equal even if the tube has a nonuniform cross section.

At constant potential difference, the resistance of any electric circuit is halved, the value of heat produced will be :

Thomson coefficient of a conductor is 10μV/K. The two ends of it are kept at 50℃ and 60℃ respectively. Amount of heat absorbed by the conductor when a charge of 10C flows through it is(a) 1000 J(b) 100 J(c) 100 mJ(d) 1 mJ

Assertion   :  Coloured spectrum is seen when we look through a muslin cloth.
Reason       : It is due to the diffraction of white light on passing through fine slits.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

Which of the following can be deflected by applying magnetic field ?

Coherent sources are obtained in the use of double prism experiment :

The force with which a magnet attracts objects like iron is called ....................... .