This chapter is currently out of syllabus
1
JEE Main 2019 (Online) 8th April Morning Slot
+4
-1
Out of Syllabus
The wavelength of the carrier waves in a modern optical fiber communication network is close to :
A
1500 nm
B
2400 nm
C
600 nm
D
900 nm
2
JEE Main 2019 (Online) 12th January Evening Slot
+4
-1
Out of Syllabus
To double the covering range of a TV transmittion tower, its height should be multiplied by :
A
4
B
2
C
$$\sqrt 2$$
D
$${1 \over {\sqrt 2 }}$$
3
JEE Main 2019 (Online) 12th January Morning Slot
+4
-1
Out of Syllabus
A 100 V carrier wave is made to vary between 160 V and 40 V by a modulating signal. What is the modulation index ?
A
0.5
B
0.6
C
0.4
D
0.3
4
JEE Main 2019 (Online) 11th January Evening Slot
+4
-1
Out of Syllabus
An amplitude modulated signal is plotted below :

Which one of the following best describes the above signal ?
A
(1 + 9sin (2$$\pi$$ $$\times$$ 104 t)) sin(2.5$$\pi$$ $$\times$$ 105t) V
B
(9 + sin (4$$\pi$$ $$\times$$ 104 t)) sin(5$$\pi$$ $$\times$$ 105t) V
C
(9 + sin (2$$\pi$$ $$\times$$ 104 t)) sin(2.5$$\pi$$ $$\times$$ 105t) V
D
(9 + sin (2.5$$\pi$$ $$\times$$ 104 t)) sin(2$$\pi$$ $$\times$$ 104t) V
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