Moving Charges and Magnetism — Physics STD 12 Science — Question

For small currents, ‘X’ obeys Ohm’s law. But when large currents are passed through the same conductor, it deviates from ohmic behaviour. Identify X.

The high temperature required to initiate the nuclear fusion reaction is to overcome the _______ present between the atoms.

1 volt = ?

A 20cm long capillary tube is dipped in water. The water rises up to 8cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be:

1. 8cm
2. 6cm
3. 10cm
4. 20cm

Unit of induced emf is:

Principle of existence of electromagnetic waves was given by:

If an electric dipole is placed in an electric field, then the value of the torque acting on it will be:

Assertion  :  from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells. 

Reason      : The energetics b-particles emitted in the decay of  damage the bone marrow.

(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.

Water flows through two identical tubes A and B. A volume V₀ of water passes through the tube A and 2 V₀ through B in a given time. Which of the followinmay be correct?

1. Flow in both the tubes are steady.
2. Flow in both the tubes are turbulent.
3. Flow is steady in A but turbulent in B.
4. Flow is steady in B but turbulent in A.