Physics Syllabus (JEE Main)
Q. The power factor of an AC circuit is defined as the ratio of:
A.
Real power to apparent power
B.
Apparent power to real power
C.
Voltage to current
D.
Current to voltage
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Solution
The power factor is defined as the ratio of real power to apparent power.
Correct Answer: A — Real power to apparent power
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Q. The rate of heat transfer by conduction is directly proportional to the area and the temperature gradient. This is described by which law?
A.
Newton's Law of Cooling
B.
Fourier's Law of Heat Conduction
C.
Stefan-Boltzmann Law
D.
Ohm's Law
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Solution
Fourier's Law of Heat Conduction states that the rate of heat transfer by conduction is directly proportional to the area and the temperature gradient.
Correct Answer: B — Fourier's Law of Heat Conduction
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Q. The rate of heat transfer by conduction is directly proportional to which of the following?
A.
Temperature difference
B.
Surface area
C.
Material thickness
D.
All of the above
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Solution
The rate of heat transfer by conduction is directly proportional to the temperature difference between the two ends.
Correct Answer: A — Temperature difference
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Q. The restoring force in a simple harmonic motion is directly proportional to:
A.
Displacement
B.
Velocity
C.
Time
D.
Mass
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Solution
Restoring force F = -kx, where k is the spring constant and x is the displacement.
Correct Answer: A — Displacement
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Q. The right-hand rule is used to determine the direction of?
A.
Magnetic field
B.
Current
C.
Force
D.
All of the above
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Solution
The right-hand rule can be used to determine the direction of the magnetic field, current, and force in electromagnetic situations.
Correct Answer: D — All of the above
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Q. The RMS speed of a gas is 250 m/s. What is the kinetic energy per molecule of the gas?
A.
0.5 * m * (250)^2
B.
0.25 * m * (250)^2
C.
0.75 * m * (250)^2
D.
1.5 * m * (250)^2
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Solution
The kinetic energy per molecule is given by KE = (1/2) * m * v^2. Thus, KE = 0.5 * m * (250)^2.
Correct Answer: A — 0.5 * m * (250)^2
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Q. The RMS speed of a gas is 300 m/s. What is the speed of sound in the gas if the ratio of specific heats is 1.4?
A.
300 m/s
B.
400 m/s
C.
500 m/s
D.
600 m/s
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Solution
Speed of sound = sqrt(γRT/M) = sqrt(1.4 * (300^2)) = 400 m/s.
Correct Answer: B — 400 m/s
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Q. The RMS speed of a gas is 400 m/s. What is the speed of sound in the gas if the ratio of specific heats is 1.4?
A.
400 m/s
B.
560 m/s
C.
700 m/s
D.
800 m/s
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Solution
The speed of sound in a gas is given by c = sqrt(γRT/M). For an ideal gas, c is approximately 1.4 times the RMS speed.
Correct Answer: B — 560 m/s
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Q. The shape of a soap bubble is spherical because:
A.
It minimizes volume
B.
It maximizes surface area
C.
It minimizes surface area for a given volume
D.
It is the only stable shape
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Solution
A soap bubble adopts a spherical shape because it minimizes the surface area for a given volume, which is energetically favorable due to surface tension.
Correct Answer: C — It minimizes surface area for a given volume
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Q. The Stefan-Boltzmann Law relates to which mode of heat transfer?
A.
Conduction
B.
Convection
C.
Radiation
D.
Insulation
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Solution
The Stefan-Boltzmann Law relates to radiation, stating that the total energy radiated per unit surface area is proportional to the fourth power of the black body's temperature.
Correct Answer: C — Radiation
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Q. The surface tension of a liquid can be measured using which of the following methods?
A.
Barometer method
B.
Capillary rise method
C.
Hydrometer method
D.
Manometer method
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Solution
The capillary rise method is commonly used to measure surface tension by observing the height to which a liquid rises in a capillary tube.
Correct Answer: B — Capillary rise method
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Q. The temperature is measured as 25°C with an error of 1°C. What is the range of possible true values?
A.
24°C to 26°C
B.
25°C to 27°C
C.
23°C to 25°C
D.
26°C to 28°C
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Solution
True value can be in the range of (Measured value - Error) to (Measured value + Error) = 25°C ± 1°C = 24°C to 26°C.
Correct Answer: A — 24°C to 26°C
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Q. The time period of a satellite in a low Earth orbit is approximately how many minutes?
A.
90 minutes
B.
60 minutes
C.
120 minutes
D.
30 minutes
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Solution
The time period of a satellite in a low Earth orbit is approximately 90 minutes due to its close proximity to the Earth.
Correct Answer: A — 90 minutes
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Q. The time period of a simple harmonic oscillator is given by T = 2π√(m/k). If the mass is doubled, what will be the new time period?
A.
T
B.
2T
C.
√2 T
D.
T/√2
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Solution
If the mass is doubled, the new time period T' = 2π√(2m/k) = √2 * (2π√(m/k)) = √2 * T. Thus, the time period increases.
Correct Answer: B — 2T
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Q. The total energy in a simple harmonic oscillator is given by which of the following?
A.
1/2 kA^2
B.
kA
C.
mgh
D.
1/2 mv^2
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Solution
Total energy E = 1/2 kA^2, where A is the amplitude.
Correct Answer: A — 1/2 kA^2
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Q. The total mechanical energy in a simple harmonic oscillator is given by which of the following?
A.
1/2 kA^2
B.
1/2 mv^2
C.
kA
D.
mv^2
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Solution
Total mechanical energy in SHM is E = 1/2 kA^2, where A is the amplitude.
Correct Answer: A — 1/2 kA^2
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Q. The unit of electric charge in SI is?
A.
Coulomb
B.
Ampere
C.
Volt
D.
Ohm
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Solution
The SI unit of electric charge is Coulomb (C).
Correct Answer: A — Coulomb
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Q. The unit of energy in the SI system is:
A.
Joule
B.
Calorie
C.
Watt
D.
Newton
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Solution
The SI unit of energy is Joule (J).
Correct Answer: A — Joule
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Q. The unit of pressure in SI is:
A.
Pascal
B.
Bar
C.
Torr
D.
Atmosphere
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Solution
The SI unit of pressure is Pascal (Pa), defined as one newton per square meter (N/m²).
Correct Answer: A — Pascal
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Q. The unit of pressure in the SI system is:
A.
Pascal
B.
Bar
C.
Torr
D.
Atmosphere
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Solution
The SI unit of pressure is Pascal (Pa), defined as one newton per square meter (N/m²).
Correct Answer: A — Pascal
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Q. The value of (x^2)^3 is equal to?
A.
x^5
B.
x^6
C.
x^7
D.
x^8
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Solution
Using the power of a power property, (a^m)^n = a^(m*n), we get (x^2)^3 = x^(2*3) = x^6.
Correct Answer: B — x^6
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Q. The weight of an object is measured as 10 kg with a 0.1 kg error. What is the maximum possible weight?
A.
10.1 kg
B.
10.2 kg
C.
10 kg
D.
9.9 kg
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Solution
Maximum possible weight = Measured weight + Absolute error = 10 + 0.1 = 10.1 kg.
Correct Answer: A — 10.1 kg
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Q. The weight of an object is measured as 200 g with a possible error of 5 g. What is the range of the true weight?
A.
195 g to 205 g
B.
200 g to 205 g
C.
195 g to 200 g
D.
200 g to 210 g
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Solution
True weight range = Measured value ± Absolute error = 200 ± 5 = 195 g to 205 g.
Correct Answer: A — 195 g to 205 g
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Q. The work done in moving a charge from a point A to point B in an electric field is equal to the change in what?
A.
Electric potential energy
B.
Electric potential
C.
Electric field strength
D.
Charge
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Solution
The work done in moving a charge in an electric field is equal to the change in electric potential energy.
Correct Answer: A — Electric potential energy
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Q. Two blocks of masses 2 kg and 3 kg are connected by a light string over a frictionless pulley. If the 3 kg block is hanging, what is the acceleration of the system?
A.
1.2 m/s²
B.
2 m/s²
C.
3 m/s²
D.
4 m/s²
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Solution
Using Newton's second law, the net force is (3 kg * 9.8 m/s²) - (2 kg * a) = (2 kg + 3 kg) * a. Solving gives a = 1.2 m/s².
Correct Answer: A — 1.2 m/s²
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Q. Two blocks of masses 2 kg and 3 kg are connected by a light string over a frictionless pulley. If the 3 kg block is released from rest, what is the acceleration of the system?
A.
1.2 m/s²
B.
2 m/s²
C.
3 m/s²
D.
4 m/s²
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Solution
Using Newton's second law, the net force is (3 kg - 2 kg) * g = 1 kg * 9.8 m/s². The total mass is 5 kg, so a = F/m = 9.8 N / 5 kg = 1.96 m/s², approximately 2 m/s².
Correct Answer: B — 2 m/s²
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Q. Two capacitors, C1 = 2μF and C2 = 3μF, are connected in series. What is the equivalent capacitance?
A.
1.2μF
B.
5μF
C.
6μF
D.
0.6μF
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Solution
For capacitors in series, the equivalent capacitance C_eq is given by 1/C_eq = 1/C1 + 1/C2. Thus, 1/C_eq = 1/2 + 1/3 = 5/6, so C_eq = 6/5 = 1.2μF.
Correct Answer: A — 1.2μF
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Q. Two capacitors, C1 and C2, are connected in series. What is the equivalent capacitance?
A.
C1 + C2
B.
1 / (1/C1 + 1/C2)
C.
C1 * C2 / (C1 + C2)
D.
C1 - C2
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Solution
The equivalent capacitance of capacitors in series is given by 1 / (1/C1 + 1/C2).
Correct Answer: B — 1 / (1/C1 + 1/C2)
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Q. Two cars are moving towards each other at speeds of 50 km/h and 70 km/h. If they are 200 meters apart, how long will it take for them to meet?
A.
5 seconds
B.
10 seconds
C.
15 seconds
D.
20 seconds
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Solution
Relative speed = 50 km/h + 70 km/h = 120 km/h = 33.33 m/s. Time = Distance/Speed = 200 m / 33.33 m/s = 6 seconds.
Correct Answer: B — 10 seconds
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Q. Two cars are moving towards each other with speeds of 50 km/h and 70 km/h. How long will it take for them to collide if they are 200 meters apart?
A.
5 seconds
B.
10 seconds
C.
15 seconds
D.
20 seconds
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Solution
Relative speed = 50 km/h + 70 km/h = 120 km/h = 33.33 m/s. Time = Distance / Relative speed = 200 m / 33.33 m/s = 6 seconds.
Correct Answer: B — 10 seconds
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