KCET SERIES Physics
Alternating Current
28 previous year questions.
Volume: 28 Ques
Yield: High
High-Yield Trend
3
2026 1
2025 1
2022 1
2020 1
2019 5
2018 1
2017 3
2016 3
2015 3
2013 2
2011 1
2009 2
2008 1
2003 Chapter Questions 28 MCQs
01
PYQ 2003
easy
physics ID: kcet-200
The time taken by AC of 50 Hz in reacting from zero to the maximum value is
1
2
3
4
02
PYQ 2008
medium
physics ID: kcet-200
The value of alternating emf in the given circuit will be
1
220 V
2
140 V
3
100 V
4
20 V
03
PYQ 2008
medium
physics ID: kcet-200
A current of is flowing at in the primary coil of a transformer. If the voltage produced in the secondary coil is and of power is lost, then the current in the secondary will be
1
2.5 A
2
5 A
3
0.25 A
4
0.5 A
04
PYQ 2009
easy
physics ID: kcet-200
An electric heater rated and is connected to mains. The current drawn by it is
1
2.5 A
2
0.4 A
3
1.25 A
4
0.8 A
05
PYQ 2011
medium
physics ID: kcet-201
A transformer works on the principle of
1
self induction
2
electrical inertia
3
mutual induction
4
magnetic effect of the electrical current
06
PYQ 2011
medium
physics ID: kcet-201
In an A.C. circuit, V and I are given by V=150 sin(150 t) volt and I=150 A. The power dissipated in the circuit is
1
106 W
2
150 W
3
5625 W
4
zero
07
PYQ 2013
medium
physics ID: kcet-201
In series circuit, the potential differences across each element is . Now the value of the resistance alone is doubled, then across and respectively
1
20 V, 10 V, 10 V
2
20 V, 20 V, 20 V
3
20 V, 40 V, 40 V
4
10 V, 20 V, 20 V
08
PYQ 2013
medium
physics ID: kcet-201
For a transformer, the turns ratio is and its efficiency is . The current flowing in the primary coil is and the voltage applied to it is . Then the voltage and the current flowing in the secondary coil are _________ respectively.
1
150 V, 1.5 A
2
300 V, 0.5 A
3
300 V, 1.5 A
4
150 V, 0.5 A
09
PYQ 2013
medium
physics ID: kcet-201
A series combination of resistor and capacitor is connected to an source of angular frequency . Keeping the voltage same, if the frequency is changed to , the current becomes half of the original current. Then the ratio of the capacitive reactance and resistance at the former frequency is
1
2
3
4
10
PYQ 2015
medium
physics ID: kcet-201
The average power dissipated in a pure inductor is
1
2
3
zero
4
11
PYQ 2015
medium
physics ID: kcet-201
A transformer is used to light lamp from mains. If the main current is , the efficiency of the transformer is
1
0.9
2
0.95
3
0.96
4
0.99
12
PYQ 2015
medium
physics ID: kcet-201
In an circuit, at resonance
1
the current and voltage are in phase
2
the impedance is maximum
3
the current is minimum
4
the current leads the voltage by
13
PYQ 2016
medium
physics ID: kcet-201
The value of current in a circuit is . The average value of current over a cycle is
1
2
3
Zero
4
14
PYQ 2016
medium
physics ID: kcet-201
In a series circuit an alternating and current are given by the equation The average power dissipated in the circuit over a cycle of is
1
2
3
4
Zero
15
PYQ 2016
medium
physics ID: kcet-201
A capacitor of capacitance is connected to an source and an Ammeter. If the source voltage varies as , the reading of the ammeter is
1
50 mA
2
70.7 mA
3
5.0 mA
4
7.07 mA
16
PYQ 2017
medium
physics ID: kcet-201
A coil of inductive reactance and resistance is connected to a , supply. The time lag between maximum voltage and current is
1
2
3
4
17
PYQ 2018
easy
physics ID: kcet-201
Which of the following, represents the variation of inductive reactance with the frequency of voltage source (v) ?
1
2
3
4
18
PYQ 2018
medium
physics ID: kcet-201
In Karnataka, the normal domestic power supply AC is 220 V, 50 Hz. Here 220 V and 50 Hz refer to
1
Peak value of voltage and frequency
2
rm s value of voltage and frequency
3
Mean value of voltage and frequency
4
Peak value of voltage and angular frequency
19
PYQ 2018
medium
physics ID: kcet-201
A 100 W bulb is connected to an AC source of 220 V, 50 Hz. Then the current flowing through the bulb is
1
2
3
4
20
PYQ 2018
easy
physics ID: kcet-201
In the series LCR circuit, the power dissipation is through
1
R
2
L
3
C
4
Both L and C
21
PYQ 2018
medium
physics ID: kcet-201
A step-up transformer operates on a 230 V line and a load current of 2 A. The ratio of primary and secondary windings is 1 : 25. Then the current in the primary is
1
25 A
2
50 A
3
100 A
4
12.5 A
22
PYQ 2019
medium
physics ID: kcet-201
The frequency of an alternating current is 50 Hz. What is the minimum time taken by current to reach its peak value from rms value?
1
2
s
3
s
4
s
23
PYQ 2020
medium
physics ID: kcet-202
A 220 V A.C supply is connected between points A and B as shown in figure what will be the potential difference V across the capacitor?
1
220 V
2
110 V
3
0
4
24
PYQ 2022
medium
physics ID: kcet-202
If a voltage across a bulb rated 220 V, 100 W drops by 2.5 % of rated value. the percentage of rated value by which the power would decrease is
1
5%
2
20%
3
10%
4
2.5%
25
PYQ 2025
medium
physics ID: kcet-202
In domestic electric mains supply, the voltage and the current are
1
DC voltage and AC current
2
AC voltage and AC current
3
AC voltage and DC current
4
DC voltage and DC current
26
PYQ 2026
medium
physics ID: kcet-202
A small town with a demand of 900 kW of electric power at 220 V is situated 20 km away from an electric power generating station. The two-wires line has resistance per unit length of . The town gets power from the line through 45000 V to 220 V stepdown transformer at a substation in the town. The line power loss in the form of heat is
1
4 kW
2
8 kW
3
40 kW
4
80 kW
27
PYQ 2026
medium
physics ID: kcet-202
In a circuit containing a pure resistor connected to an AC source,
1
Voltage leads the current by 90
2
Current leads the voltage by 90
3
Voltage and current are in same phase with each other
4
Current leads the voltage by 180
28
PYQ 2026
medium
physics ID: kcet-202
A light bulb rated 100 W is connected to an AC source of 220 V, 50 Hz. The rms current through the bulb is
1
0.454 A
2
0.545 A
3
2.20 A
4
0.22 A