63.

64.

65.

66.

67.

68.

69.

Calculate the minimum sampling frequency to avoid aliasing when a continuous time signal
is given by x(t) =5cos400zt:

(¢) 100 Hz (B) 200 Hz
(C) 300 Hz (D) 400 Hz
1 (1-2 *)
The Z transform of a signal is given by X(z) = ar Its final value is :
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4
(೮0 1 ന) Infinite

Phantom loading for testing energy meters is used :
(A) To isolate pressure coil and current coil circuits
(B) To reduce power loss during loading
( To test energy meters with low current rating
(0) To test energy meters with large current rating

A spring controlled moving iron voltmeter draws a current of 1 milliampere for full scale
value of 100 V. If it draws a current of 0.5 milliampere, the meter reading is:

(A) 25V (B) 50V
(0) 100V (0) 200V

A clamp-on ammeter measures 50 A, when wrapped around a current carrying conductor.
If the winding turns on the jaws of the meter equal 8, what is the actual value of conductor
current?

(A) 400A (8) 50%
(൭ 1954 (0) 6.95 ^

A single phase energy meter operating on 230 V and 5 A for 5 hours makes 1940 revolutions.
If the energy meter constant is 400, power factor of the load is :

(A) 1 (B) 08
(C) 0.7 (D) 06

If the secondary winding of a current transformer is opened when the primary winding is
carrying current, which of the following occurs?

(A) Transformer will burn immediately
(B) High induced emf is produced in the secondary winding

(C) Flux density in core gets weakened

(D) High current is produced in secondary winding

15 080/2023
[P.T.0.]