Electrical Energy and Power NEET Questions

Physics - Current Electricity

Electrical Energy and Power MCQ Questions


13.
An electric iron of 1 kW operating at 200 V is used for 10 hours in a month. Cost of energy at ₹5 per unit is:
A.
₹5
B.
₹25
C.
₹50
D.
₹10
😑 View Answer Rough Work Error
ANSWER :
C. ₹50
14.
Joule's law of heating states that the heat produced in a conductor of resistance R, carrying a current I for time t is:
A.
H = I/Rt
B.
H = IR²t
C.
H = IRt²
D.
H = I²Rt
😑 View Answer Rough Work Error
ANSWER :
D. H = I²Rt
15.
If the current in a heater is doubled, the heat produced per unit time becomes:
A.
One-fourth
B.
Double
C.
Four times
D.
Half
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ANSWER :
C. Four times
16.
An electric kettle has two coils. When connected in series, water boils in time t₁; when in parallel, in time t₂. The ratio t₁ : t₂ is:
A.
1 : 2
B.
1 : 4
C.
4 : 1
D.
2 : 1
😑 View Answer Rough Work Error
ANSWER :
C. 4 : 1
17.
An electric bulb is marked 220 V, 100 W. If the supply voltage drops to 110 V, the power consumed will be:
A.
100 W
B.
200 W
C.
25 W
D.
50 W
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ANSWER :
C. 25 W
18.
Three bulbs of 60 W, 100 W and 200 W (all rated for the same voltage V) are connected in series across voltage V. The bulb that glows brightest is:
A.
200 W bulb
B.
All glow equally
C.
100 W bulb
D.
60 W bulb
😑 View Answer Rough Work Error
ANSWER :
D. 60 W bulb