Alternating Current | Physics JEE Main questions with Solutions

Q 1 :
Primary side of a transformer is connected to 230 V, 50 Hz supply. Turns ratio of primary to secondary winding is 10 : 1. Load resistance connected to secondary side is 46 Ω. The power consumed in it is [2024]

12.5 W
10.0 W
11.5 W
12.0 W

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4

(C) $\frac{V_{1}}{V_{2}} = \frac{N_{1}}{N_{2}}$

$\frac{230}{V_{2}} = \frac{10}{1}$

$V_{2} = 23 V$

$Power consumed = \frac{V_{2}^{2}}{R} = \frac{23 \times 23}{46} = 11.5 W$

Q 2 :
A transformer has an efficiency of 80% and works at 10 V and 4 kW. If the secondary voltage is 240 V, then the current in the secondary coil is [2024]

1.59A
13.33 A
1.33 A
15.1 A

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(B) $Efficiency η = 80 %, P_{i} = 4 kW = 4000 W$

$V_{P} = 10 V,$ $V_{S} = 240 V$

$For primary coil : I_{P} = \frac{P_{i}}{V_{P}} = \frac{4000}{10} = 400 A$

$η = \frac{V_{S} I_{S}}{V_{P} I_{P}} \Rightarrow \frac{80}{100} = \frac{240 I_{S}}{10 \times 400}$

$\Rightarrow I_{S} = 13.33 A$

Q 3 :
A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230 V by the transformer. The current in the primary of the transformer is 5 A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is _____A. [2024]

0%

(45) $0.9 P_{i} = P_{o u t}$

$P_{i} = V I$

$P_{i} = 2.3 \times 10^{3} (5) = 11.5 \times 10^{3} W$

$P_{o u t} = (230) i_{2}$

$(0.9) (11.5 \times 10^{3}) = 230 i_{2}$

$i_{2} = \frac{(0.9) (11.5 \times 10^{3})}{230} = 0.045 \times 10^{3}$

$i_{2} = 45 A$

Q 4 :
Primary coil of a transformer is connected to 220 V AC. The primary and secondary turns of the transformer are 100 and 10 respectively. The secondary coil of the transformer is connected to two series resistances shown in figure. The output voltage $(V_{0})$ is ______. [2024]

7 V
15 V
44 V
22 V

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(1)

$\frac{E_{P}}{E_{S}} = \frac{N_{P}}{N_{S}} = \frac{100}{10} = 10$

$E_{S} = \frac{E_{P}}{10} = \frac{220}{10} = 22 V$

$V_{0} = (i) (7 k Ω) \Rightarrow V_{0} = 7 V$

Topic Question Set

Q 1 :
Primary side of a transformer is connected to 230 V, 50 Hz supply. Turns ratio of primary to secondary winding is 10 : 1. Load resistance connected to secondary side is 46 Ω. The power consumed in it is [2024]

Q 2 :
A transformer has an efficiency of 80% and works at 10 V and 4 kW. If the secondary voltage is 240 V, then the current in the secondary coil is [2024]

0%

Q 4 :
Primary coil of a transformer is connected to 220 V AC. The primary and secondary turns of the transformer are 100 and 10 respectively. The secondary coil of the transformer is connected to two series resistances shown in figure. The output voltage $(V_{0})$ is ______. [2024]

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Topic Question Set

Q 1 : Primary side of a transformer is connected to 230 V, 50 Hz supply. Turns ratio of primary to secondary winding is 10 : 1. Load resistance connected to secondary side is 46 Ω. The power consumed in it is [2024]

Q 2 : A transformer has an efficiency of 80% and works at 10 V and 4 kW. If the secondary voltage is 240 V, then the current in the secondary coil is [2024]

0%

Q 4 : Primary coil of a transformer is connected to 220 V AC. The primary and secondary turns of the transformer are 100 and 10 respectively. The secondary coil of the transformer is connected to two series resistances shown in figure. The output voltage (V0) is ______. [2024]

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Q 1 :
Primary side of a transformer is connected to 230 V, 50 Hz supply. Turns ratio of primary to secondary winding is 10 : 1. Load resistance connected to secondary side is 46 Ω. The power consumed in it is [2024]

Q 2 :
A transformer has an efficiency of 80% and works at 10 V and 4 kW. If the secondary voltage is 240 V, then the current in the secondary coil is [2024]

Q 4 :
Primary coil of a transformer is connected to 220 V AC. The primary and secondary turns of the transformer are 100 and 10 respectively. The secondary coil of the transformer is connected to two series resistances shown in figure. The output voltage $(V_{0})$ is ______. [2024]