Q. If the potential difference across a capacitor is halved, what happens to the energy stored in the capacitor? (2019)
A.
Halved
B.
Doubled
C.
Remains the same
D.
Quadrupled
Show solution
Solution
The energy stored in a capacitor is given by U = 1/2 CV^2. If V is halved, the energy becomes U' = 1/2 C(V/2)^2 = 1/8 CV^2, which is halved.
Correct Answer: A — Halved
Learn More →
Q. If the potential difference across a capacitor is increased, what happens to the charge stored in it? (2020)
A.
It decreases
B.
It remains the same
C.
It increases
D.
It becomes zero
Show solution
Solution
The charge (Q) stored in a capacitor is directly proportional to the potential difference (V) across it, given by Q = CV.
Correct Answer: C — It increases
Learn More →
Q. If the potential difference between two points is 10 V and the work done to move a charge of 2 C between these points is: (2020)
A.
5 J
B.
10 J
C.
20 J
D.
40 J
Show solution
Solution
Work done (W) = Charge (Q) × Potential difference (V) = 2 C × 10 V = 20 J.
Correct Answer: C — 20 J
Learn More →
Q. If the radius of a rotating object is halved while keeping the angular velocity constant, what happens to its linear velocity? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
Linear velocity v = rω, so if r is halved and ω remains constant, v also halves.
Correct Answer: B — It halves
Learn More →
Q. If the radius of curvature of a concave mirror is 20 cm, what is its focal length? (2022)
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
Show solution
Solution
The focal length (f) of a concave mirror is given by f = R/2, where R is the radius of curvature. Thus, f = 20 cm / 2 = 10 cm.
Correct Answer: B — 10 cm
Learn More →
Q. If the radius of curvature of a convex lens is 20 cm, what is its focal length? (2022)
A.
10 cm
B.
20 cm
C.
30 cm
D.
40 cm
Show solution
Solution
The focal length f of a lens is given by f = R/2. Therefore, f = 20 cm / 2 = 10 cm.
Correct Answer: B — 20 cm
Learn More →
Q. If the radius of curvature of a convex mirror is 20 cm, what is its focal length? (2022)
A.
10 cm
B.
20 cm
C.
30 cm
D.
40 cm
Show solution
Solution
The focal length (f) of a mirror is given by f = R/2. For a convex mirror, R is positive, so f = 20 cm / 2 = 10 cm.
Correct Answer: A — 10 cm
Learn More →
Q. If the resistance of a conductor is doubled while the voltage remains constant, what happens to the current? (2020)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
According to Ohm's Law, if the resistance (R) is doubled and the voltage (V) remains constant, the current (I) will be halved (I = V/R).
Correct Answer: B — It halves
Learn More →
Q. If the vapor pressure of pure solvent is 100 mmHg, and the vapor pressure of the solution is 80 mmHg, what is the relative lowering of vapor pressure? (2022)
A.
0.2
B.
0.1
C.
0.5
D.
0.3
Show solution
Solution
Relative lowering of vapor pressure = (P° - P) / P° = (100 - 80) / 100 = 0.2.
Correct Answer: A — 0.2
Learn More →
Q. If the vapor pressure of pure solvent is 100 mmHg, and the vapor pressure of the solution is 80 mmHg, what is the mole fraction of the solute? (2022)
A.
0.2
B.
0.4
C.
0.5
D.
0.8
Show solution
Solution
Using Raoult's Law: P_solution = X_solvent * P_solvent. X_solvent = P_solution / P_solvent = 80/100 = 0.8, thus X_solute = 1 - X_solvent = 0.2.
Correct Answer: B — 0.4
Learn More →
Q. If the voltage across a capacitor in an AC circuit is 100 V RMS, what is the peak voltage? (2022)
A.
100 V
B.
141.42 V
C.
200 V
D.
70.71 V
Show solution
Solution
The peak voltage (V_peak) is calculated as V_peak = V_rms × √2 = 100 V × √2 ≈ 141.42 V.
Correct Answer: B — 141.42 V
Learn More →
Q. If the voltage across a resistor is increased from 5V to 10V, what happens to the current through the resistor if the resistance is constant? (2021)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
Show solution
Solution
According to Ohm's law, if voltage increases and resistance remains constant, current will also increase proportionally.
Correct Answer: A — It doubles
Learn More →
Q. If the voltage across an inductor is 100 V and the current through it is 2 A, what is the inductive reactance? (2023)
A.
50 Ω
B.
200 Ω
C.
100 Ω
D.
25 Ω
Show solution
Solution
Inductive reactance (X_L) is given by X_L = V/I. Here, X_L = 100 V / 2 A = 50 Ω.
Correct Answer: A — 50 Ω
Learn More →
Q. If two charges of +2 µC and -2 µC are placed 1 m apart, what is the net electric field at the midpoint? (2023)
A.
0 N/C
B.
4 N/C
C.
2 N/C
D.
8 N/C
Show solution
Solution
The electric fields due to both charges at the midpoint cancel each other out, resulting in a net electric field of 0 N/C.
Correct Answer: A — 0 N/C
Learn More →
Q. If two resistors of 4Ω and 12Ω are connected in series, what is the total voltage across them if the current flowing is 2A? (2020)
A.
32V
B.
24V
C.
16V
D.
8V
Show solution
Solution
Total resistance R = 4Ω + 12Ω = 16Ω. Voltage V = I * R = 2A * 16Ω = 32V.
Correct Answer: B — 24V
Learn More →
Q. If two resistors of 4Ω and 6Ω are connected in parallel, what is the equivalent resistance? (2022)
A.
2.4Ω
B.
10Ω
C.
24Ω
D.
1.5Ω
Show solution
Solution
Using the formula for parallel resistors, 1/R_eq = 1/R1 + 1/R2 = 1/4 + 1/6 = 5/12, R_eq = 12/5 = 2.4Ω.
Correct Answer: A — 2.4Ω
Learn More →
Q. If two resistors of 5Ω and 10Ω are connected in series, what is the total resistance? (2021)
A.
5Ω
B.
10Ω
C.
15Ω
D.
20Ω
Show solution
Solution
In series, R_total = R1 + R2 = 5Ω + 10Ω = 15Ω.
Correct Answer: C — 15Ω
Learn More →
Q. In a body-centered cubic (BCC) structure, how many atoms are there in one unit cell? (2022)
Show solution
Solution
In a body-centered cubic (BCC) structure, there are 2 atoms per unit cell (1 from the center and 1 from the corners).
Correct Answer: B — 2
Learn More →
Q. In a capacitor, if the plate area is increased while keeping the distance constant, what happens to the capacitance? (2023)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
Show solution
Solution
Increasing the plate area while keeping the distance constant increases the capacitance, as capacitance is directly proportional to the area of the plates.
Correct Answer: A — Increases
Learn More →
Q. In a chemical reaction, what does the term 'activation energy' refer to? (2023)
A.
Energy released during the reaction
B.
Energy required to initiate the reaction
C.
Energy needed to maintain the reaction
D.
Energy that is lost
Show solution
Solution
Activation energy is the minimum energy required to initiate a chemical reaction.
Correct Answer: B — Energy required to initiate the reaction
Learn More →
Q. In a circuit with a 10Ω resistor and a 5V battery, what is the power consumed by the resistor? (2023)
Show solution
Solution
Power P = V^2/R = 5^2/10 = 25/10 = 2.5W.
Correct Answer: B — 2W
Learn More →
Q. In a circuit with a 10Ω resistor and a 5Ω resistor in series, what is the total voltage across the circuit if the current is 2A? (2023)
A.
30V
B.
20V
C.
10V
D.
40V
Show solution
Solution
Total resistance R = 10Ω + 5Ω = 15Ω. Voltage V = I * R = 2A * 15Ω = 30V.
Correct Answer: B — 20V
Learn More →
Q. In a circuit with a 12V battery and two 4Ω resistors in series, what is the current flowing through the circuit? (2023)
Show solution
Solution
Total resistance R = 4Ω + 4Ω = 8Ω. Current I = V/R = 12V/8Ω = 1.5A.
Correct Answer: B — 2A
Learn More →
Q. In a circuit with a 15V battery and a 5Ω resistor, what is the voltage drop across the resistor? (2019)
Show solution
Solution
The voltage drop across the resistor is equal to the battery voltage, which is 15V.
Correct Answer: C — 15V
Learn More →
Q. In a circuit with a 15V battery and two resistors of 5Ω and 10Ω in series, what is the voltage drop across the 10Ω resistor? (2022)
A.
5V
B.
10V
C.
15V
D.
0V
Show solution
Solution
The total resistance is 15Ω. The current I = V/R = 15V/15Ω = 1A. Voltage drop across 10Ω = I * R = 1A * 10Ω = 10V.
Correct Answer: B — 10V
Learn More →
Q. In a circuit with a 24V battery and a 6Ω resistor, what is the power consumed by the resistor? (2020)
A.
48W
B.
72W
C.
96W
D.
144W
Show solution
Solution
Power (P) can be calculated using P = V^2 / R. Here, P = 24V^2 / 6Ω = 96W.
Correct Answer: B — 72W
Learn More →
Q. In a circuit with a 24V battery and a total resistance of 8Ω, what is the power consumed by the circuit? (2023)
A.
72 W
B.
48 W
C.
36 W
D.
24 W
Show solution
Solution
Power P = V^2/R = 24^2/8 = 576/8 = 72 W.
Correct Answer: B — 48 W
Learn More →
Q. In a circuit with a 9V battery and two resistors of 3Ω and 6Ω in series, what is the voltage across the 6Ω resistor? (2022)
Show solution
Solution
Total resistance R_total = 3Ω + 6Ω = 9Ω. Current I = V/R_total = 9V/9Ω = 1A. Voltage across 6Ω = I * R = 1A * 6Ω = 6V.
Correct Answer: B — 6V
Learn More →
Q. In a circuit with a 9V battery and two resistors of 3Ω and 6Ω in series, what is the current flowing through the circuit? (2022)
Show solution
Solution
Total resistance R = 3Ω + 6Ω = 9Ω. Current I = V/R = 9V/9Ω = 1A.
Correct Answer: B — 2A
Learn More →
Q. In a circuit with a voltage of 24V and a current of 6A, what is the resistance? (2020)
Show solution
Solution
Using Ohm's Law, R = V/I = 24V / 6A = 4Ω.
Correct Answer: D — 8Ω
Learn More →
Showing 271 to 300 of 2725 (91 Pages)