MCQ
A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence, the rod gains gravitational potential energy. The work required to do this comes from:
  • A
    The current source.
  • B
    The magnetic field.
  • C
    The induced electric field due to the changing magnetic field.
  • D
    The lattice structure of the material of the rod.

Answer

  1. The current source.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Assertion  :   Silicon is preferred over germanium for making semiconductor devices.

Reason      : The energy gap for germanium is more than the energy gap of silicon.

(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 figure represents the variation of particle momentum and the associated de-Broglie wavelength

(a)

(b)

(c)

(d)

Using visible light what is the shortest wavelength which can be measured?

The effective resistance between the points  A and  B in the figure is

(a) 5Ω

(b) 2 Ω

(c) 3 Ω

(d) 4 Ω

A parallel plate capacitor is charged. If the plates are pulled apart:

Basically, the product modulator is

(a) An amplifier

(b) A mixer

(c) A frequency separator

(d) A phase separator

Light from a hydrogen discharge tube is incident on the cathode of a photoelectric cell, the work function of the cathode surface is 4.2 eV. In order to reduce the photocurrent to zero the voltage of the anode relative to the cathode must be made?

Find out the value of current through 2Ω resistance for the given circuit

(a) 5 A

(b) 2 A

(c) Zero

(d) 4 A

If two wires having resistance R and 2R. Both joined in series and in parallel then ratio of heat generated in this situation, applying the same voltage,

(a) 2 : 1   

(b) 1 : 2

(c) 2 : 9    

(d) 9 : 2

In the figure shown, for an angle of incidence 45°, at the top surface, what is the minimum refractive index needed for total internal reflection at vertical face

(a)  

(b)

(c)  

(d)