1
JEE Main 2022 (Online) 29th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

The activity of a radioactive material is 2.56 $$\times$$ 10$$-$$3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 $$\times$$ 10$$-$$5 Ci ?

A
30 days
B
35 days
C
40 days
D
25 days
2
JEE Main 2022 (Online) 28th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

Following statements related to radioactivity are given below :

(A) Radioactivity is a random and spontaneous process and is dependent on physical and chemical conditions.

(B) The number of un-decayed nuclei in the radioactive sample decays exponentially with time.

(C) Slope of the graph of loge (no. of undecayed nuclei) Vs. time represents the reciprocal of mean life time ($$\tau$$).

(D) Product of decay constant ($$\lambda$$) and half-life time (T1/2) is not constant.

Choose the most appropriate answer from the options given below :

A
(A) and (B) only
B
(B) and (D) only
C
(B) and (C) only
D
(C) and (D) only
3
JEE Main 2022 (Online) 28th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The Q-value of a nuclear reaction and kinetic energy of the projectile particle, Kp are related as :

A
Q = Kp
B
(Kp + Q) < 0
C
Q < Kp
D
(Kp + Q) > 0
4
JEE Main 2022 (Online) 27th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements :

Statement I : In hydrogen atom, the frequency of radiation emitted when an electron jumps from lower energy orbit (E1) to higher energy orbit (E2), is given as hf = E1 $$-$$ E2

Statement II : The jumping of electron from higher energy orbit (E2) to lower energy orbit (E1) is associated with frequency of radiation given as f = (E2 $$-$$ E1)/h

This condition is Bohr's frequency condition.

In the light of the above statements, choose the correct answer from the options given below :

A
Both Statement I and Statement II are true.
B
Both Statement I and Statement II are false.
C
Statement I is correct but Statement II is false.
D
Statement I is incorrect but Statement II is true.
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