Electronics and Communication Engineering - Electromagnetic Field Theory

36. 

The torque (in mm) acting on a circular current loop of radius 1 mm in the xy plane, connected at the origin and with current 0.1 A, flowing in the sense of increasing in a magnetic field
is

A.
B.
C. 10-12p
D. - 10-12p

Answer: Option B

Explanation:

t = M x B


37. 

Which one of the following potential does not satisfy Laplace's equations?

A. v = 10 xy
B. v = p cos φ
C.
D. v = f cos φ + 10

Answer: Option B

Explanation:

.


38. 

A rectangular waveguide measures 3 x 4.5 cm internally and has a 10 GHz signal propagated in it. Calculate the wave impedance for dominant mode.

A. 130 p
B. 1.3 p
C. 120 p
D. 12 p

Answer: Option B

Explanation:

Wave impedance

.


39. 

Calculate wave impedance for TE mode

A. (377)Ω
B. 226 Ω
C.
D. 629 Ω

Answer: Option D

Explanation:

.


40. 

In a 100 turn coil, if the flux through each turn is (t3 - 2t)mWb, the magnitude of the induced emf in the coil at a time of 4 sec is

A. 46 mV
B. 56 mV
C. 4.6 V
D. 5.6 V

Answer: Option C

Explanation:

E = 100 (3t2 - 2) 100(46) 4600 mV

4.6 V.