Nuclei

Four statements are given (A is mass number) : Choose the correct answer from the options given below :

1. A and D are true, but B and C are false
2. B and D are true, but A and C are false
3. B and C are true, but A and D are false
4. A and C are true, but B and D are false

An unknown nucleus has a nuclear density of 2.29 1017 kg/m3 and mass of 19.926 10-27 kg. Its mass number A is approximately : (Take R0 = 1.2 10-15 m, 4π = 12.56)

1. 16
2. 20
3. 12
4. 19

Consider the following nuclear reaction 238U 234Th + 4He Take masses of 238U, 234Th and 4He as 238.050 u, 234.043 u and 4.003 u, respectively. The Q value for the reaction, in keV, is: [Given: 1 u = 931.5 MeV c-2]

1. 3740
2. 3726
3. 3730
4. 3736

29082X Y e+ Z - P e- Q In the nuclear emission stated above, the mass number and atomic number of the product Q respectively, are

1. 280, 81
2. 286, 80
3. 288, 82
4. 286, 81

Water is used as a coolant in a nuclear reactor because of its

1. high thermal expansion coefficient
2. high specific heat capacity
3. low density
4. low boiling point

Select the correct statements among the following : Choose the most appropriate answer from the options given below :

1. A, B and C only
2. A, B and D only
3. A and B only
4. C and D only

The half life of a radioactive substance is 20 minutes. In how much time, the activity of substance drops to ( 116 )th of its initial value?

1. 40 minutes
2. 60 minutes
3. 80 minutes
4. 20 minutes

A nucleus of mass number 189 splits into two nuclei having mass number 125 and 64. The ratio of radius of two daughter nuclei respectively is

1. 1 : 1
2. 4 : 5
3. 5 : 4
4. 25 : 16

In the given nuclear reaction, the element X is 2211Na X + e+ +

1. 2311Na
2. 2310Ne
3. 2210Ne
4. 2212Mg

Given below are two statements In the light of the above statements, choose the most appropriate answer from the options given below :

1. Statement I is incorrect but statement II is correct
2. Both statement I and statement II are correct
3. Both statement I and statement II are incorrect
4. Statement I is correct but statement II is incorrect