1
JEE Main 2022 (Online) 27th July Evening Shift
+4
-1

The activity of a radioactive material is $$6.4 \times 10^{-4}$$ curie. Its half life is 5 days. The activity will become $$5 \times 10^{-6}$$ curie after :

A
7 days
B
15 days
C
25 days
D
35 days
2
JEE Main 2022 (Online) 27th July Morning Shift
+4
-1

What is the half-life period of a radioactive material if its activity drops to $$1 / 16^{\text {th }}$$ of its initial value in 30 years?

A
9.5 years
B
8.5 years
C
7.5 years
D
10.5 years
3
JEE Main 2022 (Online) 26th July Evening Shift
+4
-1

A nucleus of mass $$M$$ at rest splits into two parts having masses $$\frac{M^{\prime}}{3}$$ and $${{2M'} \over 3}(M' < M)$$. The ratio of de Broglie wavelength of two parts will be :

A
1 : 2
B
2 : 1
C
1 : 1
D
2 : 3
4
JEE Main 2022 (Online) 26th July Evening Shift
+4
-1

Mass numbers of two nuclei are in the ratio of $$4: 3$$. Their nuclear densities will be in the ratio of

A
4 : 3
B
$$\left(\frac{3}{4}\right)^{\frac{1}{3}}$$
C
1 : 1
D
$$\left(\frac{4}{3}\right)^{\frac{1}{3}}$$
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