Q. If the wavelength of a photon is doubled, what happens to its energy? (2019)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
Energy is inversely proportional to wavelength (E = hc/λ). If λ is doubled, E is halved.
Correct Answer:
B
— It halves
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Q. If the wavelength of light in vacuum is 600 nm, what is its wavelength in water (n = 1.33)? (2023)
A.
450 nm
B.
600 nm
C.
750 nm
D.
800 nm
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Solution
Wavelength in medium = Wavelength in vacuum / n. Thus, λ = 600 nm / 1.33 ≈ 450 nm.
Correct Answer:
A
— 450 nm
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Q. In a hydrogen atom, what is the energy of the electron in the ground state? (Use Rydberg's constant R = 13.6 eV) (2023)
A.
-13.6 eV
B.
0 eV
C.
-1.51 eV
D.
-3.4 eV
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Solution
The energy of the electron in the ground state of hydrogen is -13.6 eV.
Correct Answer:
A
— -13.6 eV
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Q. In a magnetic field, the direction of the magnetic force on a charged particle is given by which rule?
A.
Right-hand rule
B.
Left-hand rule
C.
Fleming's right-hand rule
D.
Fleming's left-hand rule
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Solution
The direction of the magnetic force on a charged particle moving in a magnetic field is determined by the right-hand rule.
Correct Answer:
A
— Right-hand rule
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Q. In a parallel circuit with two resistors of 6 ohms and 3 ohms, what is the total resistance?
A.
2 ohms
B.
4 ohms
C.
1.5 ohms
D.
9 ohms
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Solution
The total resistance in parallel is given by 1/R_total = 1/R1 + 1/R2. Thus, 1/R_total = 1/6 + 1/3 = 1/2, so R_total = 2 ohms.
Correct Answer:
A
— 2 ohms
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Q. In a parallel circuit, if one resistor fails, what happens to the rest of the circuit? (2022)
A.
All resistors fail
B.
Current stops flowing
C.
The circuit remains functional
D.
Voltage drops to zero
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Solution
In a parallel circuit, if one resistor fails, the other paths remain functional, allowing current to continue flowing.
Correct Answer:
C
— The circuit remains functional
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Q. In a parallel circuit, if one resistor fails, what happens to the total resistance? (2020)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes infinite
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Solution
In a parallel circuit, if one resistor fails, the total resistance decreases because there are fewer paths for current to flow.
Correct Answer:
B
— Decreases
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Q. In a series circuit with a 12 V battery and two resistors of 4 Ω and 8 Ω, what is the current flowing through the circuit?
A.
0.5 A
B.
1 A
C.
1.5 A
D.
2 A
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Solution
Total resistance R_total = R1 + R2 = 4 Ω + 8 Ω = 12 Ω. Using Ohm's Law, I = V/R = 12 V / 12 Ω = 1 A.
Correct Answer:
B
— 1 A
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Q. In an adiabatic process, the temperature of a gas decreases. What happens to its pressure? (2021)
A.
Increases
B.
Decreases
C.
Remains constant
D.
Depends on volume
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Solution
In an adiabatic process, as the temperature decreases, the pressure also decreases due to the ideal gas law.
Correct Answer:
B
— Decreases
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Q. In which medium does sound travel the slowest?
A.
Air
B.
Water
C.
Steel
D.
Vacuum
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Solution
Sound travels slowest in air compared to water and solids like steel.
Correct Answer:
A
— Air
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Q. What happens to the total current in a parallel circuit if more branches are added? (2023)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
In a parallel circuit, adding more branches increases the total current because each branch provides an additional path for current to flow.
Correct Answer:
A
— Increases
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Q. What is the change in internal energy of a gas that absorbs 500 J of heat and does 200 J of work? (2022)
A.
300 J
B.
500 J
C.
700 J
D.
1000 J
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Solution
Using the first law of thermodynamics: ΔU = Q - W = 500 J - 200 J = 300 J.
Correct Answer:
A
— 300 J
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Q. What is the change in internal energy of a gas that absorbs 500 J of heat and does 200 J of work on the surroundings? (2023)
A.
300 J
B.
500 J
C.
700 J
D.
900 J
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Solution
ΔU = Q - W = 500 J - 200 J = 300 J.
Correct Answer:
A
— 300 J
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Q. What is the change in internal energy of a system if 500 J of work is done on it and 200 J of heat is lost? (2023)
A.
300 J
B.
500 J
C.
700 J
D.
900 J
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Solution
Change in internal energy (ΔU) = Q - W = -200 J - 500 J = -300 J.
Correct Answer:
A
— 300 J
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Q. What is the critical angle for a glass medium (n = 1.5) when light travels from glass to air? (2020)
A.
30 degrees
B.
41.8 degrees
C.
48.6 degrees
D.
60 degrees
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Solution
Using the formula for critical angle: sin(c) = n2/n1, we find c = sin^(-1)(1/1.5) ≈ 41.8 degrees.
Correct Answer:
B
— 41.8 degrees
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Q. What is the critical angle for light traveling from glass (n = 1.5) to air (n = 1)? (2019)
A.
30 degrees
B.
41.8 degrees
C.
48.6 degrees
D.
60 degrees
Show solution
Solution
Using the formula sin(c) = n2/n1, we find sin(c) = 1/1.5, thus c = sin^(-1)(2/3) ≈ 41.8 degrees.
Correct Answer:
B
— 41.8 degrees
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Q. What is the decibel level of a sound that is 10 times more intense than a reference sound at 0 dB?
A.
10 dB
B.
20 dB
C.
30 dB
D.
40 dB
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Solution
The decibel scale is logarithmic; a sound 10 times more intense is 10 dB.
Correct Answer:
A
— 10 dB
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Q. What is the decibel level of a sound that is 10 times more intense than the reference level of 0 dB?
A.
10 dB
B.
20 dB
C.
30 dB
D.
40 dB
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Solution
A sound that is 10 times more intense than the reference level is 10 dB.
Correct Answer:
A
— 10 dB
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Q. What is the decibel level of a sound that is perceived as the threshold of hearing? (2022)
A.
0 dB
B.
10 dB
C.
20 dB
D.
30 dB
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Solution
The threshold of hearing is defined as 0 dB.
Correct Answer:
A
— 0 dB
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Q. What is the direction of the magnetic field around a current-carrying conductor? (2019)
A.
From North to South
B.
From South to North
C.
Clockwise
D.
Counterclockwise
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Solution
The direction of the magnetic field around a current-carrying conductor is given by the right-hand rule, which indicates a counterclockwise direction when viewed from the positive current side.
Correct Answer:
D
— Counterclockwise
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Q. What is the effect called when sound waves spread out after passing through a narrow opening? (2019)
A.
Reflection
B.
Refraction
C.
Diffraction
D.
Interference
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Solution
The spreading out of sound waves after passing through a narrow opening is known as diffraction.
Correct Answer:
C
— Diffraction
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Q. What is the energy of a photon with a frequency of 5 x 10^14 Hz? (Planck's constant h = 6.626 x 10^-34 J·s) (2021)
A.
3.31 x 10^-19 J
B.
1.32 x 10^-19 J
C.
2.48 x 10^-19 J
D.
4.97 x 10^-19 J
Show solution
Solution
Energy (E) = h * frequency = 6.626 x 10^-34 J·s * 5 x 10^14 Hz = 3.31 x 10^-19 J.
Correct Answer:
A
— 3.31 x 10^-19 J
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Q. What is the equivalent resistance of two resistors of 4 ohms and 6 ohms connected in series?
A.
10 ohms
B.
24 ohms
C.
2.4 ohms
D.
0.67 ohms
Show solution
Solution
In series, the equivalent resistance is the sum: R_eq = R1 + R2 = 4 Ω + 6 Ω = 10 Ω.
Correct Answer:
A
— 10 ohms
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Q. What is the equivalent resistance of two resistors of 4 ohms and 6 ohms in series?
A.
10 ohms
B.
24 ohms
C.
2.4 ohms
D.
0.67 ohms
Show solution
Solution
In series, the equivalent resistance is the sum: R_eq = R1 + R2 = 4 Ω + 6 Ω = 10 Ω.
Correct Answer:
A
— 10 ohms
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Q. What is the equivalent resistance of two resistors, R1 = 4Ω and R2 = 6Ω, in parallel? (2022)
A.
2.4Ω
B.
10Ω
C.
24Ω
D.
1.5Ω
Show solution
Solution
The formula for equivalent resistance in parallel is 1/R_eq = 1/R1 + 1/R2. Thus, 1/R_eq = 1/4 + 1/6 = 5/12, so R_eq = 12/5 = 2.4Ω.
Correct Answer:
A
— 2.4Ω
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Q. What is the equivalent resistance of two resistors, R1 and R2, in parallel? (2022)
A.
R1 + R2
B.
R1 * R2 / (R1 + R2)
C.
1 / (1/R1 + 1/R2)
D.
R1 - R2
Show solution
Solution
The formula for equivalent resistance (R_eq) of two resistors in parallel is given by 1 / (1/R1 + 1/R2).
Correct Answer:
C
— 1 / (1/R1 + 1/R2)
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Q. What is the focal length of a diverging lens if the image distance is -15 cm and the object distance is -10 cm? (2023)
A.
-30 cm
B.
-20 cm
C.
-15 cm
D.
-10 cm
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Solution
Using the lens formula 1/f = 1/v - 1/u, we find f = -20 cm.
Correct Answer:
B
— -20 cm
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Q. What is the formula for calculating electric power? (2023)
A.
P = IV
B.
P = I^2R
C.
P = V^2/R
D.
All of the above
Show solution
Solution
The electric power can be calculated using multiple formulas: P = IV (power = current × voltage), P = I^2R (power = current squared × resistance), and P = V^2/R (power = voltage squared / resistance).
Correct Answer:
D
— All of the above
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Q. What is the formula for calculating the capacitance of a parallel plate capacitor?
A.
C = εA/d
B.
C = A/εd
C.
C = d/εA
D.
C = εd/A
Show solution
Solution
The capacitance (C) of a parallel plate capacitor is given by C = εA/d, where ε is the permittivity, A is the area of the plates, and d is the distance between them.
Correct Answer:
A
— C = εA/d
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Q. What is the formula for calculating the power consumed in an electrical circuit?
A.
P = IV
B.
P = I/R
C.
P = V/R
D.
P = IR
Show solution
Solution
The power consumed in an electrical circuit is given by the formula P = IV, where P is power, I is current, and V is voltage.
Correct Answer:
A
— P = IV
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