1
AIIMS 2018
MCQ (Single Correct Answer)
+1
-0.33

The half-life of a radioactive substance is $$20 \mathrm{~min}$$. The approximate time interval $$\left(t_2-t_1\right)$$ between the time $$t_2$$, when $$\frac{2}{3}$$ of it has decayed and time $$t_1$$ when $$\frac{1}{3}$$ of it had decayed is

A
14 min
B
20 min
C
28 min
D
7 min
2
AIIMS 2018
MCQ (Single Correct Answer)
+1
-0.33

Assertion If electrons in an atom were stationary, then they would fall into the nucleus.

Reason Electrostatic force of attraction acts between negatively charged electrons and positive nucleus.

A
Both Assertion and Reason are correct, Reason is the correct explanation of Assertion
B
Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
C
Assertion is correct and Reason is incorrect
D
Assertion is incorrect and Reason is correct
3
AIIMS 2018
MCQ (Single Correct Answer)
+1
-0.33

Assertion Radioactive nuclei emits $$\beta^{-}$$-particles.

Reason Electrons exist inside the nucleus.

A
Both Assertion and Reason are correct, Reason is the correct explanation of Assertion
B
Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
C
Assertion is correct and Reason is incorrect
D
Assertion is incorrect and Reason is correct
4
AIIMS 2017
MCQ (Single Correct Answer)
+1
-0.33

A nuclear explosive is designed to deliver $$1 \mathrm{~MW}$$ power in the form of heat energy. If the explosion is designed with nuclear fuel consisting of $$U^{235}$$ to run a reactor at this power level for one year, then the amount of fuel needed is (Given energy per fission is $$200 \mathrm{~MeV}$$)

A
$$1 \mathrm{~kg}$$
B
$$0.01 \mathrm{~kg}$$
C
$$3.84 \mathrm{~kg}$$
D
$$0.384 \mathrm{~kg}$$
AIIMS Subjects
EXAM MAP