Assertion: A charged particle can be accelerated in a cyclotron by the alternate distribution of the field.

Reason: Energy of the charged particle is increased by the field applied. 

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion:  At rest, radium is decayed into Radon and an $\mathrm{\alpha }$-particle. They both moves back to back of each other. 

Reason: Splitting of radioactive particle is based on conservation of linear momentum.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion:  In electromagnetic waves electric field and magnetic field lines are perpendicular to each other.
Reason: Electric field and magnetic field are self sustaining.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Gauss's law shows diversion when inverse square law is not obeyed.

Reason: Gauss's law is a consequence of conservation of charges.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Which of the following current must be zero in an unbiased PN junction diode?

• Current due to majority charge carriers (both electrons and holes).

• Current due to minority charge carriers (both electrons and holes).

• Current due to majority and minority charge carriers

• Current due to majority and minority charge carriers (only holes).

46.

In a convex lens of focal length F, the minimum distance between an object and its real image must be

• 3F

• 4F

• $\frac{3}{2}$F

• 2F

In Young's double slit experiment, fringe order is represented by m, then fringe width is

• Independent of m

• Directly proportional to m

• Directly proportional to ( 2m + 1 )

• Inversely proportional to (2m + 1 )

Half life of a radio-active element is 8 years, how much amount will be present after 32 years?

• $\frac{1}{4}$

• $\frac{1}{8}$

• $\frac{1}{16}$

• $\frac{1}{32}$

Total energy of the electron in hydrogen atom above 0 eV leads to

• continuation of energy states

• large number of discrete ionised states

• balmer series

• paschen series

Gamma decay takes place

• Prior to alpha decay.

• Prior to beta decay.

• Prior to positron decay.

• Due to de-excitment of nuclear levels.