1
NEET 2018
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is
A
20
B
10
C
30
D
15
2
NEET 2017
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Radioactive material 'A' has decay constant '8 $$\lambda $$' and material 'B' has decay constant '$$\lambda $$'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'A' will be e ?
A
$${1 \over {7\lambda }}$$
B
$${1 \over {8\lambda }}$$
C
$${1 \over {9\lambda }}$$
D
$${1 \over {\lambda }}$$
3
NEET 2017
MCQ (Single Correct Answer)
+4
-1
The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is
A
1
B
4
C
0.5
D
2
4
NEET 2016 Phase 2
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
The half-life of a radioactive substance is 30 minutes. The time (in minutes) taken between 40% decay and 85% decay of the same radioactive substance is
A
15
B
30
C
45
D
60
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