1
MHT CET 2025 25th April Morning Shift
MCQ (Single Correct Answer)
+1
-0

A radioactive element has rate of disintegration 9000 disintegration per minute at a particular instant. After two minutes it becomes 3000 disintegration per minute. The decay constant per minute is

A
$0.5 \log _{\mathrm{c}} 3$
B
$0.2 \log _{\mathrm{e}} 3$
C
$0.5 \log _{\mathrm{e}} 2$
D
$0.2 \log _{\mathrm{e}} 2$
2
MHT CET 2025 23rd April Evening Shift
MCQ (Single Correct Answer)
+1
-0

In hydrogen atom, transition from the state $\mathrm{n}=6$ to $n=1$ results in ultraviolet radiation. Infrared radiation will be obtained in the transition

A
$\mathrm{n}=3$ to $\mathrm{n}=1$
B
$\mathrm{n}=4$ to $\mathrm{n}=2$
C
$n=6$ to $n=2$
D
$n=5$ to $n=3$
3
MHT CET 2025 23rd April Evening Shift
MCQ (Single Correct Answer)
+1
-0

A radioactive element ${ }_{92}^{242} \mathrm{X}$ emits two $\alpha$ particles, one electron and two positrons. The product nucleus is represented by ${ }_{\mathrm{p}}^{234} \mathrm{Y}$. The value of $P$ is

A
87
B
85
C
92
D
96
4
MHT CET 2025 23rd April Morning Shift
MCQ (Single Correct Answer)
+1
-0

The activity of radioactive sample is measured as $\mathrm{N}_0$ counts per minute at time $\mathrm{t}=0$, and $\frac{\mathrm{N}_0}{\mathrm{e}}$ counts per minute at time $\mathrm{t}=3$ minute, The activity reduces to half its value in time (in minute)

A
$\frac{1}{3} \log _{\mathrm{e}} 2$
B
$3 \log _{\mathrm{e}} 2$
C
$3 \log _{10} 2$
D
$\frac{3}{\log _{10} 2}$
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