1
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A metal surface is illuminated by a radiation of wavelength 4500 $$\mathop A\limits^o $$. The ejected photo-electron enters a constant magnetic field of 2 mT making an angle of 90$$^\circ$$ with the magnetic field. If it starts revolving in a circular path of radius 2 mm, the work function of the metal is approximately :

A
1.36 eV
B
1.69 eV
C
2.78 eV
D
2.23 eV
2
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

A radioactive nucleus can decay by two different processes. Half-life for the first process is 3.0 hours while it is 4.5 hours for the second process. The effective half-life of the nucleus will be:

A
3.75 hours
B
0.56 hours
C
0.26 hours
D
1.80 hours
3
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

The positive feedback is required by an amplifier to act an oscillator. The feedback here means :

A
External input is necessary to sustain ac signal in output.
B
A portion of the output power is returned back to the input.
C
Feedback can be achieved by LR network.
D
The base-collector junction must be forward biased.
4
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

A sinusoidal wave y(t) = 40sin(10 $$\times$$ 106 $$\pi$$t) is amplitude modulated by another sinusoidal wave x(t) = 20sin (1000 $$\pi$$t). The amplitude of minimum frequency component of modulated signal is :

A
0.5
B
0.25
C
20
D
10
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