Entry Test MCQ :: Electromagnetism
21.
An instrument which can measure potential without drawing any current is
A.
voltmeter
B.
galvanometer
C.
cathode ray oscilloscope (CRO)
D.
ammeter
Answer: Option C
Explanation:
22.
The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12?. Galvanometer resistance is
Answer: Option D
Explanation:
23.
When the coil of the galvanometer is in equilibrium then the deflecting couple is
A.
zero
B.
equal to the restoring couple
C.
greater than the restoring couple
D.
smaller than the restoring couple
Answer: Option B
Explanation:
24.
The sensitivity of a galvanometer is given by
Answer: Option A
Explanation:
25.
Which one of the following is not an electromechanical instrument?
A.
galvanometer
B.
voltmeter
C.
ammeter
D.
AC transformer and DC generator
Answer: Option D
Explanation:
26.
Minimum current required to produce a deflection of 1 mm on a scale at a distance of 1 meter is
A.
0.1 A
B.
1:00 AM
C.
current sensitivity
D.
1 m A
Answer: Option C
Explanation:
27.
In a multi range ammeter as the range increases
A.
shunt value decreases
B.
shunt value increases
C.
shunt value remains the same
D.
none of the above
Answer: Option A
Explanation:
28.
While measuring the unknown resistance the help of slide wire bridge a greatest accuracy can be achieved when
A.
a most sensitive galvanometer is used
B.
a steady voltage cell is used
C.
the balance point is close to the middle of the wire
D.
a high resistance box is used in one of its gap
Answer: Option C
Explanation:
29.
A sensitive galvanometer gives full-scale deflection with 100 mV. If the resistance of the galvanometer is 50? the maximum current that can flow through safely is
Answer: Option A
Explanation:
30.
An ammeter measures the total current flowing through a circuit when it is connected
A.
in series with the circuit
B.
in parallel with circuit
C.
in series with any of the parallel resistances in the circuit
D.
in parallel with any of the series resistances in the circuit
Answer: Option A
Explanation:
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