A nucleus disintegrates into two nuclear parts which have their velocities in the ratio 2 : 1. The ratio of their nuclear size will be
21/3 : 1
1 : 31/2
31/2 : 1
1 : 21/2
A block having 12g of element is placed in a room. This element is a radioactive element with half-life of 15 yr. After how many years will there be just 1.5 g of the element in the box?
40 yr
45 yr
20 yr
15 yr
A7 Li target is bombarded with a proton beam current of 10-4 A for one hour to produce 7Be of activity 1.8 × 108 disintegrations per second. Assuming that one 7Be radioactive nuclei is produced by bombarding 1000 protons, its half-life is
0.87 × 107 s
0.2 × 107 s
0.67 × 108 s
0.87 × 106 s
Two radioactive materials X1 and X2 have decay constants 6 and 3A respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X1 to that of X2 will be after a time
B.
The ratio of number of nuclei of X1 to that of X2 after time t,
∴
∴ ( N = N0 e-λt )
⇒ 3λt = 1
∴ t =
A neutron in a nuclear reactor collides head on elastically with the nucleus of a carbon atom initially at rest. The fraction of kinetic energy transferred from the neutron to the carbon atom is
Assertion: Thermonuclear fusion reactions may become the source of unlimited power for the mankind.
Reason: A single fusion event involving isotopes of hydrogen produces more energy from nuclear fission of
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.
An atom of mass number 15 and atomic number 7 captures an a-particle and then emits a proton. The mass number and atomic number of the resulting atom will be respectively
14 and 12
15 and 3
16 and 4
18 and 8
A zener diode is specified as having a breakdown voltage of 9.1 V, with a maximum power dissipation of 364 mW. What is the maximum current the diode can handle?
40 mA
60 mA
50 mA
45 mA
Assertion: Generally heavy nuclei are unstable.
Reason: It has more neutrons and protons.
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
The half-life of radium is 1600 years. What is the fraction of sample undecayed after 6400 years?