1. A battery of emf 4 V has a internal resistance of 0.2 ohms, when a load resistance of 1.8 Ohms connected across it,the potential difference across its terminal will be
Answer : 3.6 V
Explanation:-
Battery emf is 4 V, Total circuit resistance is 0.2+1.8 = 2 Ohms
Current flowing through circuit is Voltage/Resistance
I = 4/2=2 A
Potential difference Across Resistance is V=IR
= 2*1.8
= 3.6 V
2. An iron ring 10 cm in diameter and 8 square cm in cross section is wound with 300 turns of wire , For a flux density of 1.2 wb/m^2 and a relative permeability of 500, the inductance of the coil is
Answer : B. 0.1440H
Explanation:-
3. A resistance of 10 ohms is connected across a supply of 200V. If a resistance R is now connected is parallel with a 10ohms resistance, the current drawn from the supply gets doubled. The value of the unknown resistance R is
Answer : B. 10ohms
Explanation:-
4. 1Kwh is equal to
Answer : A. 860 K.cal
Explanation:-
5. Electrical conductiong material possessing negative temperature co-efficient is
Answer : carbon
Explanation:-
6. When temperature of the insulating material increases its resistivity
Answer : B. decreases
Explanation:-
7. Manganin wire is commonly used for
Answer : C. instrument shunt
Explanation:-
8. Self inductance of two coiils are L1=2H and L2=8H. The coil L1 produces a magnetic files of 80 microwebers of which only 60 microwb are linked with coil L2. The mutual inductance of the two coils is
Answer : C. 3H
Explanation:-
9. A copper wire has resistance of 0.85 ohms at 20 deg C, temperature co-efficient of resistance of copper at 0 deg C is 0.004 deg C. The resistance at 40deg C is
Answer : B. 0.9129 Ohm
Explanation:-
10. A copper wire of 1cm diameter has a resistance of 0.15 ohm, it is drawn under pressure and its diameter was reduced to 50 %. The new value of resistance of the wire is
Answer : B. 2.4 Ohm
Explanation:-
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