A sample of radioactive elements contains 4×10104×1010 active nuclei. If half-life of element is 10 days, then the number of decayed nuclei after 30 days is
1. 0.5×1010
2. 2×1010
3. 3.5×1010
4. 1×1010
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:
1. 6.62 yr
2. 5 yr
3. 3.2 yr
4. 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
1. 3.70 gm
2. 6.30 gm
3. 1.35 gm
4. 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
1. 1
2. 1/2
3. 1.5
4. 3/4
Complete the equation for the following fission process-
U23592+n10→Sr9038+........
1. Xe14354+3 n10
2. Xe14554
3. Xe14257
4. Xe14254+n10
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) ?
1. 21/3 : 1
2. 1 : 21/3
3. 31/2 : 1
4. 1 : 31/2
The half-life of a radioactive material is 3h. If the initial amount is 300g, then after 18h, it will remain
1. 4.68 g
2. 46.8 g
3. 9.375 g
4. 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-
1. 10 min
2. 20 min
3. 30 min
4. 40 min
When two deuterium nuclei fuse together to form a tritium nuclei, we get a
1. Neutron
2. Deutron
3. α-particle
4. Proton
The most penetrating radiation out of the following is
1. γ-rays
2. α-particles
3. β-rays
4. X-rays