Physics - Nuclei - Quiz-3

Atomic weight of boron is 10.81 and it has two isotopes ${}_{5}^{10}B a n d {}_{5}^{11}B$ . Then, the ratio of atoms of ${}_{5}^{10}B a n d {}_{5}^{11}B$ in nature would be

0%

19 : 81
0%

10 : 11
0%

15 : 16
0%

81 : 19

The half-life of radium is 1600 yr. The fraction of a sample of radium that would remain

after 6400 yr [1991]

0%

$\frac{1}{4}$
0%

$\frac{1}{2}$
0%

$\frac{1}{8}$
0%

$\frac{1}{16}$

The count rate of a Geiger Muller counter for the radiation of a radioactive material of half-life 30 min decreases to 5 $s^{- 1}$ after 2 h. The initial count rate was [1995]

0%

20 $s^{- 1}$
0%

25 $s^{- 1}$
0%

80 $s^{- 1}$
0%

625 $s^{- 1}$

An element A decays into element C by a two step process

$A \to B + {}_{2}H e^{4} B \to C + 2 e^{-}$

then [1989]

0%

A and C are isotopes
0%

A and C are isobars
0%

A and B are isotopes
0%

A and B are isobars

The radius R of a nuclear matter varies with A as

0%

$R α A^{2 / 3}$
0%

$R α A^{1 / 3}$
0%

$R α A^{0}$
0%

$R α A$

Number of nuclei of a radioactive substance at time t = 0 are 2000 and 1800 at time t = 2s. Number of nuclei left after t = 6s is [MGIMS 2010]

0%

1442
0%

1554
0%

1652
0%

1458

In a radioactive material, the activity at time $t_{1}$ is $R_{1}$ and at a later time, $t_{2}$ is $R_{2}$ . If the decay constant of the material is $λ$ , then:

0%

$R_{1} = R_{2} e^{- λ (t_{1} - t_{2})}$
0%

$R_{1} = R_{2} e^{λ (t_{1} - t_{2})}$
0%

$R_{1} = R_{2} (\frac{t_{2}}{t_{1}})$
0%

$R_{1} = R_{2}$

Which of the following are suitable for the fusion process ? [2002]

0%

Light nuclei
0%

Heavy nuclei
0%

Elements lying in the middle of periodic table
0%

Elements lying in the middle of binding energy curve

An archeologist analyses the wood in a prehistoric structure and finds that $C^{14}$ (Half - life=5700 years) to $C^{12}$ is only one - fourth of that found in the cells buried plants. The age of the wood is about

0%

5700 yr
0%

2850 yr
0%

11,400 yr
0%

22,800 yr

In the nuclear reaction: $X {(n, α)}_{3} L i^{7}$ , the term X will be:

0%

${}_{5}B_{10}$
0%

${}_{5}B_{9}$
0%

${}_{5}B_{11}$
0%

${}_{2}H e^{4}$

10 g of radioactive material of half-life 15 year is kept in store for 20 years. The disintegrated material mass is [Pb. PMT 2002]

0%

12.5 g
0%

10.5 g
0%

6.03 g
0%

4.03 g

A certain mass of hydrogen is changed to helium by the process of fusion. The mass defect in the fusion reaction is 0.02866 u. The energy liberated per nucleon is: (given 1 u = 931 MeV)

0%

2.67 MeV
0%

26.7 MeV
0%

6.675 MeV
0%

13.35 MeV

One nanogram of matter converted into energy will give-

0%
90 J
0%

$9 \times 10^{3} J$
0%

$9 \times 10^{10} J$
0%

$9\times 10^{4}~J$

If a radioactive nucleus decays according to the following reaction

${}_{72}X_{180} \overset{α}{\to} X_{1} \overset{β}{\to} X_{2} \overset{α}{\to} X_{3} \overset{γ}{\to} X_{4}$

then the mass number and the atomic number of $X_{4}$ then the mass number and the atomic number of $X_{4}$ will be, respectively [MP PET 2002]

0%

172, 70
0%

172, 69
0%

172, 68
0%

171, 69

Two radioactive materials $X_{1}$ and $X_{2}$ have decay constants 10 $λ$ and $λ$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of $X_{1}$ to that of $X_{2}$ will be $\frac{1}{e}$ after a time

0%

$\frac{1}{10 λ}$
0%

$\frac{1}{11 λ}$
0%

$\frac{11}{10 λ}$
0%

$\frac{1}{9 λ}$

A radioactive material has mean-lives of 1620 yr and 520 yr for $α$ and $β$ -emission. The material decays by simultaneous $α$ and $β$ -emission. The time in which 1/4th of the material remains intact is

0%

4675 yr
0%

720 yr
0%

545 yr
0%

324 yr

The radioactivity of an element becomes $\frac{1}{64} t h$ of its original value in 60 seconds. Then the half value period is

0%

5 sec
0%

10 sec
0%

20 sec
0%

30 sec

A nucleus of ${}_{84}^{210}P o$ originally at rest emits $α$ particle with speed $ν$ . What will be the recoil speed of the daughter necleus. [DCE 2002]

0%

4 $ν$ / 206
0%

4 $ν$ / 214
0%

$ν$ / 206
0%

$ν$ / 214

An atom of mass number 15 and atomic number 7 captures an $α$ -particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be

0%

14 and 2
0%

15 and 3
0%

16 and 4
0%

18 and 8

Solar energy is mainly caused due to [2003]

0%

fusion of protons during synthesis of heavier elements
0%

gravitational contraction
0%

burning of hydrogen in the oxygen
0%

fission of uranium present in the sun

A sample of radioactive elements contains $4 \times 10^{10}$ active nuclei. If half-life of element is 10 days, then the number of decayed nuclei after 30 days is

0%

$0.5 \times 10^{10}$
0%

$2 \times 10^{10}$
0%

$3.5 \times 10^{10}$
0%

$1 \times 10^{10}$

A and B are two radioactive substances whose half-lives are 1 and 2 years respectively. Initially 10 g of A and 1 g of B is taken. The time (approximate) after which they will have the same quantity remaining is:

0%

6.62 yr
0%

5 yr
0%

3.2 yr
0%

7 yr

A sample of radioactive element has a mass of 10 gm at an instant t = 0. The approximate mass of this element in the sample after two means lives in [CBSE PMT/PDT 2003]

0%

3.70 gm
0%

6.30 gm
0%

1.35 gm
0%

2.50 gm

Given a sample of Radium-226 having half-life of 4 days. Find the probability, a nucleus disintegrates after 2 half lives [IIT-JEE 2006]

0%

1
0%

1/2
0%

1.5
0%

3/4

Complete the equation for the following fission process-

$U_{92}^{235} + n_{0}^{1} \to S r_{38}^{90} + . . . . . . . .$

0%

$X e_{{}_{54}}^{143} + 3 n_{0}^{1}$
0%

$X {e_{{}_{54}}^{145}}^{}$
0%

$X {e_{{}_{57}}^{142}}^{}$
0%

$X {e_{{}_{54}}^{142}}^{} + n_{0}^{1}$

A nucleus ruptures into two nuclear parts which have their velocity ratio equal to 2:1. What will be the ratio of their nuclear size (nuclear radius) ?

0%

$2^{1 / 3} : 1$
0%

$1 : 2^{1 / 3}$
0%

$3^{1 / 2} : 1$
0%

$1 : 3^{1 / 2}$

The half-life of a radioactive material is 3h. If the initial amount is 300g, then after 18h, it will remain

0%

4.68 g
0%

46.8 g
0%

9.375 g
0%

93.75 g

Half-life of a radioactive substance is 20 min. Difference between points of time when it is 33% disintegrated and 67% disintegrated is approximately-

0%

10 min
0%

20 min
0%

30 min
0%

40 min

When two deuterium nuclei fuse together to form a tritium nuclei, we get a

0%

Neutron
0%

Deutron
0%

$α$ -particle
0%

Proton

The most penetrating radiation out of the following is [1997]

0%

$γ$ -rays
0%

$α$ -particles
0%

$β$ -rays
0%

X-rays

0:0:1

Practice Physics Quiz Questions and Answers

0:0:1

Practice Physics Quiz Questions and Answers

Support mcqexams.com by disabling your adblocker.