Q. If the speed of light in vacuum is 3 x 10^8 m/s, what is its speed in a medium with a refractive index of 1.5?
A.
2 x 10^8 m/s
B.
2.5 x 10^8 m/s
C.
3 x 10^8 m/s
D.
1.5 x 10^8 m/s
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Solution
Speed of light in a medium = speed of light in vacuum / refractive index = (3 x 10^8 m/s) / 1.5 = 2 x 10^8 m/s.
Correct Answer: A — 2 x 10^8 m/s
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Q. If the speed of light in vacuum is 3 x 10^8 m/s, what is its speed in glass (n = 1.5)?
A.
2 x 10^8 m/s
B.
2.5 x 10^8 m/s
C.
3 x 10^8 m/s
D.
1.5 x 10^8 m/s
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Solution
The speed of light in a medium is given by v = c/n. Therefore, v = (3 x 10^8 m/s) / 1.5 = 2 x 10^8 m/s.
Correct Answer: A — 2 x 10^8 m/s
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Q. If the speed of light is 3 x 10^8 m/s, what is its value in km/s? (2021)
A.
3 x 10^5 km/s
B.
3 x 10^6 km/s
C.
3 x 10^7 km/s
D.
3 x 10^8 km/s
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Solution
To convert m/s to km/s, divide by 1000. Therefore, 3 x 10^8 m/s = 3 x 10^5 km/s.
Correct Answer: A — 3 x 10^5 km/s
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Q. If the total current in an AC circuit is 5A and the voltage is 120V, what is the impedance? (2023)
A.
24Ω
B.
20Ω
C.
30Ω
D.
15Ω
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Solution
Impedance (Z) = Voltage (V) / Current (I) = 120V / 5A = 24Ω.
Correct Answer: B — 20Ω
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Q. If the voltage across a capacitor in an AC circuit is 100 V and the capacitive reactance is 50 ohms, what is the current? (2020)
A.
2 A
B.
0.5 A
C.
5 A
D.
10 A
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Solution
Using Ohm's law, I = V/Xc = 100 V / 50 ohms = 2 A.
Correct Answer: B — 0.5 A
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Q. If the voltage across a capacitor in an AC circuit is 100 V and the capacitive reactance is 50 Ω, what is the current through the capacitor? (2021)
A.
2 A
B.
0.5 A
C.
5 A
D.
10 A
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Solution
Using Ohm's law, I = V/Xc = 100 V / 50 Ω = 2 A.
Correct Answer: B — 0.5 A
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Q. If the voltage across a capacitor in an AC circuit is 100 V and the capacitive reactance is 50 ohms, what is the current through the capacitor? (2021)
A.
2 A
B.
1 A
C.
0.5 A
D.
0.25 A
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Solution
Current I = V/Xc = 100 V / 50 ohms = 2 A.
Correct Answer: B — 1 A
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Q. If the voltage across a capacitor in an AC circuit is 100V and the capacitive reactance is 50Ω, what is the current through the capacitor? (2023)
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Solution
Current (I) = Voltage (V) / Capacitive Reactance (XC) = 100V / 50Ω = 2A.
Correct Answer: B — 2A
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Q. If the voltage across a capacitor in an AC circuit is 100V and the capacitive reactance is 50Ω, what is the current? (2021)
A.
2A
B.
0.5A
C.
5A
D.
100A
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Solution
Using Ohm's law, I = V/Xc = 100V/50Ω = 2A.
Correct Answer: B — 0.5A
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Q. If the voltage across a capacitor in an AC circuit is 100V and the capacitive reactance is 50 ohms, what is the current? (2023)
A.
2A
B.
0.5A
C.
5A
D.
10A
Show solution
Solution
Using Ohm's law, I = V/Xc = 100V/50Ω = 2A.
Correct Answer: A — 2A
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Q. If the voltage across a capacitor is 100V and the capacitive reactance is 50 ohms, what is the current through the capacitor? (2022)
A.
2 A
B.
1 A
C.
0.5 A
D.
0.25 A
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Solution
I = V/Xc = 100/50 = 2 A.
Correct Answer: B — 1 A
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Q. If the voltage across a resistor is 240V and the resistance is 60 ohms, what is the current flowing through it? (2020)
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Solution
I = V / R = 240V / 60Ω = 4A.
Correct Answer: C — 6A
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Q. If the voltage across a resistor is halved, what happens to the current through it? (2020)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
According to Ohm's law, if voltage is halved and resistance remains constant, the current also halves.
Correct Answer: B — It halves
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Q. If the volume of a gas is doubled at constant temperature, what happens to its pressure?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
According to Boyle's Law, at constant temperature, pressure is inversely proportional to volume. Therefore, if the volume is doubled, the pressure is halved.
Correct Answer: B — It halves
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Q. If the volume of a gas is halved at constant temperature, what happens to its pressure? (2023)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
According to Boyle's Law, if the volume is halved, the pressure doubles at constant temperature.
Correct Answer: A — It doubles
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Q. If the volume of a gas is halved while keeping the temperature constant, what happens to the pressure of the gas?
A.
Halves
B.
Doubles
C.
Remains the same
D.
Increases by 50%
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Solution
According to Boyle's Law, if the volume is halved, the pressure doubles.
Correct Answer: B — Doubles
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Q. If the wavelength of light is halved, what happens to the energy of the photons? (2020)
A.
It is halved
B.
It is doubled
C.
It remains the same
D.
It is quadrupled
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Solution
Energy is inversely proportional to wavelength. Halving the wavelength doubles the energy.
Correct Answer: B — It is doubled
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Q. If the wavelength of light used in a diffraction grating is increased, what happens to the angular separation of the fringes? (2023)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
The angular separation (θ) is directly proportional to the wavelength (λ). Therefore, increasing λ increases the angular separation.
Correct Answer: A — Increases
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Q. If the wavelength of light used in a double-slit experiment is increased, what happens to the fringe separation? (2022)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
Fringe separation is directly proportional to the wavelength. If the wavelength increases, the fringe separation also increases.
Correct Answer: A — Increases
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Q. If the wavelength of light used in a double-slit experiment is increased, what happens to the distance between the fringes? (2022)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
The fringe width is directly proportional to the wavelength. Therefore, increasing the wavelength increases the distance between the fringes.
Correct Answer: A — Increases
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Q. If the wavelength of light used in a single-slit diffraction experiment is increased, what will happen to the position of the first minimum? (2022)
A.
It moves closer to the center
B.
It moves away from the center
C.
It remains unchanged
D.
It disappears
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Solution
The position of the first minimum in single-slit diffraction is given by a sin(θ) = λ. Increasing λ will cause θ to increase, moving the minimum away from the center.
Correct Answer: B — It moves away from the center
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Q. If the wavelength of light used in a single-slit diffraction experiment is increased, what happens to the width of the central maximum? (2023)
A.
It decreases
B.
It increases
C.
It remains the same
D.
It becomes zero
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Solution
The width of the central maximum in single-slit diffraction is directly proportional to the wavelength. Increasing the wavelength increases the width.
Correct Answer: B — It increases
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Q. If two charges +Q and -Q are placed at a distance 'd' apart, what is the electric field at the midpoint? (2020)
A.
0
B.
kQ/d^2
C.
kQ/(2d^2)
D.
kQ/d
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Solution
At the midpoint, the electric fields due to +Q and -Q cancel each other out, resulting in a net electric field of 0.
Correct Answer: A — 0
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Q. If two identical capacitors of 4 µF each are connected in series, what is the equivalent capacitance?
A.
2 µF
B.
4 µF
C.
6 µF
D.
8 µF
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Solution
C_eq = 1 / (1/C1 + 1/C2) = 1 / (1/4 + 1/4) = 2 µF.
Correct Answer: A — 2 µF
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Q. If two resistors of 4Ω and 6Ω are connected in series, what is the total resistance? (2023)
A.
10Ω
B.
24Ω
C.
2.4Ω
D.
12Ω
Show solution
Solution
In series, R_eq = R1 + R2 = 4Ω + 6Ω = 10Ω.
Correct Answer: A — 10Ω
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Q. In a Carnot engine operating between 500 K and 300 K, what is the maximum efficiency of the engine? (2021)
A.
40%
B.
60%
C.
50%
D.
20%
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Solution
Efficiency (η) = 1 - (T_cold / T_hot) = 1 - (300 K / 500 K) = 0.4 or 40%.
Correct Answer: B — 60%
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Q. In a Carnot engine operating between temperatures of 500 K and 300 K, what is the maximum efficiency? (2023)
A.
40%
B.
60%
C.
50%
D.
70%
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Solution
Efficiency (η) = 1 - (T_cold / T_hot) = 1 - (300 K / 500 K) = 0.4 or 40%.
Correct Answer: B — 60%
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Q. In a Carnot engine operating between temperatures of 500 K and 300 K, what is the efficiency of the engine? (2023)
A.
40%
B.
50%
C.
60%
D.
70%
Show solution
Solution
Efficiency (η) = 1 - (T_cold / T_hot) = 1 - (300 K / 500 K) = 0.4 or 40%.
Correct Answer: C — 60%
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Q. In a Carnot engine operating between two heat reservoirs at temperatures 500 K and 300 K, what is the maximum efficiency of the engine? (2023)
A.
40%
B.
60%
C.
80%
D.
20%
Show solution
Solution
Efficiency (η) = 1 - (T_cold / T_hot) = 1 - (300 K / 500 K) = 0.4 or 40%.
Correct Answer: B — 60%
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Q. In a circuit with a 24V battery and two 8Ω resistors in series, what is the total current? (2022)
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Solution
Total resistance R = 8Ω + 8Ω = 16Ω. Current I = V/R = 24V / 16Ω = 1.5A.
Correct Answer: B — 2A
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