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

Match List - I with List - II :

List - I List - II
(a) UV rays (i) Diagnostic tool in medicine
(b) X-rays (ii) Water purification
(c) Microwave (iii) Communication, Radar
(d) Infrared wave (iv) Improving visibility in foggy days

Choose the correct answer from the options given below :

A
(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
B
(a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
C
(a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
D
(a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
2
JEE Main 2022 (Online) 29th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The kinetic energy of emitted electron is E when the light incident on the metal has wavelength $$\lambda$$. To double the kinetic energy, the incident light must have wavelength:

A
$$\frac{\mathrm{hc}}{\mathrm{E} \lambda-\mathrm{hc}}$$
B
$$\frac{\mathrm{hc} \lambda}{\mathrm{E} \lambda+\mathrm{hc}}$$
C
$$\frac{\mathrm{h} \lambda}{\mathrm{E} \lambda+\mathrm{hc}}$$
D
$$\frac{\text { hc } \lambda}{\mathrm{E} \lambda-\mathrm{hc}}$$
3
JEE Main 2022 (Online) 29th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Find the ratio of energies of photons produced due to transition of an electron of hydrogen atom from its (i) second permitted energy level to the first level, and (ii) the highest permitted energy level to the first permitted level.

A
3 : 4
B
4 : 3
C
1 : 4
D
4 : 1
4
JEE Main 2022 (Online) 29th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

Find the modulation index of an AM wave having $$8 \mathrm{~V}$$ variation where maximum amplitude of the AM wave is $$9 \mathrm{~V}$$.

A
0.8
B
0.5
C
0.2
D
0.1
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