Other Physics · JEE Main previous year questions

383 questions asked across 19 exam years, newest first

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2005 16 questions

Q1162005 · 28 Apr 2005 · Shift 1
A heater coil is cut into two equal parts and only one part is now used in the heater. The heat generated will now be
1. A.four times
2. B.doubled
3. C.halved
4. D.one fourth
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Answer: B
Q1322005 · 28 Apr 2005 · Shift 1
Two point white dots are $1 mm$ apart on a black paper. They are viewed by eye of pupil diameter $3 mm$ . Approximately, what is the maximum distance at which these dots can be resolved by the eye? [ Take wavelength of light $= 500 nm$ ]
1. A. $1 m$
2. B. $5 m$
3. C. $3 m$
4. D. $6 m$
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Answer: B
Q1382005 · 28 Apr 2005 · Shift 1
A photocell is illuminated by a small bright source placed $1 m$ away. When the same source of light is placed $\frac{1}{2} m$ away, the number of electrons emitted by photo-cathode would
1. A.increases by a factor of 4
2. B.decreases by a factor of 4
3. C.increases by a factor of 2
4. D.decreases by a factor of 2
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Answer: A

2004 15 questions

Q702004 · 24 Apr 2004 · Shift 1
A ball is released from the top of a tower of height h meters. It takes T seconds to reach the ground. What is the position of the ball in $\frac{T}{3}$ seconds?
1. A. $\frac{8 h}{9}$ meters from the ground
2. B. $\frac{7 h}{9}$ meters from the ground
3. C. $\frac{h}{9}$ meters from the ground
4. D. $\frac{7 h}{18}$ meters from the ground
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Answer: A
Q712004 · 24 Apr 2004 · Shift 1
If $A \times B = B \times A$ , then the angle between A and B is
1. A. $\frac{π}{2}$
2. B. $\frac{π}{3}$
3. C. $π$
4. D. $\frac{π}{4}$
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Answer: C
Q732004 · 24 Apr 2004 · Shift 1
Which of the following statements is FALSE for a particle moving in a circle with a constant angular speed?
1. A.The velocity vector is tangent to the circle.
2. B.The acceleration vector is tangent to the circle.
3. C.The acceleration vector points to the centre of the circle.
4. D.The velocity and acceleration vectors are perpendicular to each other.
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Answer: B
Q742004 · 24 Apr 2004 · Shift 1
An automobile travelling with speed of 60 km/h, can brake to stop within a distance of 20 m. If the car is going twice as fast, i.e 120 km/h, the stopping distance will be
1. A.60 m
2. B.40 m
3. C.20 m
4. D.80 m
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Answer: D
Q752004 · 24 Apr 2004 · Shift 1
A ball is thrown from a point with a speed $v_{0}$ at an angle of projection θ. From the same point and at the same instant person starts running with a constant speed $\frac{v _{0}}{2}$ to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection θ?
1. A.No
2. B.Yes, $3 0^{\circ}$
3. C.Yes, $6 0^{\circ}$
4. D.Yes, $4 5^{\circ}$
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Answer: C
Q822004 · 24 Apr 2004 · Shift 1
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particles takes place in a plane. It follows that
1. A.its kinetic energy is constant
2. B.is acceleration is constant
3. C.its velocity is constant
4. D.it moves in a straight line
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Answer: A
Q832004 · 24 Apr 2004 · Shift 1
A machine gun fires a bullet of mass $40 g$ with a velocity $1200 m s^{- 1}$ . The man holding it can exert a maximum force of $144 N$ on the gun. How many bullets can he fire per second at the most?
1. A.Two
2. B.Four
3. C.One
4. D.Three
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Answer: D
Q942004 · 24 Apr 2004 · Shift 1
If the temperature of the sun were to increase from $T$ to $2 T$ and its radius from $R$ to $2 R$ , then the ratio of the radiant energy received on earth to what it was previously will be
1. A. $32$
2. B. $16$
3. C. $4$
4. D. $64$
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Answer: D
Q1112004 · 24 Apr 2004 · Shift 1
Thermistors are usually made of
1. A.metal oxides with high temperature coefficient of resistivity
2. B.metals with high temperature coefficient of resistivity
3. C.metals with low temperature coefficient of resistivity
4. D.semiconducting materials having low temperature
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Answer: A
Q1122004 · 24 Apr 2004 · Shift 1
Time taken by a $836 W$ heater to heat one litre of water from $1 0^{\circ} C$ to $4 0^{\circ} C$ is
1. A. $150 s$
2. B. $100 s$
3. C. $50 s$
4. D. $200 s$
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Answer: A
Q1132004 · 24 Apr 2004 · Shift 1
The thermo $e m f$ of a thermocouple varies with temperature $θ$ of the hot junction as $E = a θ + b θ^{2}$ in volts where the ratio $a / b$ is $70 0^{\circ} C$ . If the cold junction is kept at $0^{\circ} C$ , then the neutral temperature is
1. A. $140 0^{\circ} C$
2. B. $35 0^{\circ} C$
3. C. $70 0^{\circ} C$
4. D.No neutral temperature is possible for this termocouple.
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Answer: D
Q1172004 · 24 Apr 2004 · Shift 1
Curie temperature is the temperature above which
1. A.a ferromagnetic material becomes paramagnetic
2. B.a paramagnetic material becomes diamagnetic
3. C.a ferromagnetic material becomes diamagnetic
4. D.a paramagnetic material becomes ferromagnetic
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Answer: A
Q1212004 · 24 Apr 2004 · Shift 1
Two long conductors, separated by a distance $d$ carry current $I_{1}$ and $I_{2}$ in the same direction. They exert a force $F$ on each other. Now the current in one of them is increased to two times and its direction is reversed. The distance is also increased to $3 d$ . The new value of the force between them is
1. A. $- \frac{2 F}{3}$
2. B. $\frac{F}{3}$
3. C. $- 2 F$
4. D. $- \frac{F}{3}$
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Answer: A
Q1232004 · 24 Apr 2004 · Shift 1
The materials suitable for making electromagnets should have
1. A.high retentivity and low coercivity
2. B.low retentivity and low coercivity
3. C.high retentivity and high coercivity
4. D.low retentivity and high coercivity
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Answer: B
Q1402004 · 24 Apr 2004 · Shift 1
The manifestation of band structure in solids is due to
1. A.Bohr's correspondence principle
2. B.Pauli's exclusion principle
3. C.Heisenberg's uncertainty principle
4. D.Boltzmann's law
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Answer: B

2002 15 questions

Q762002 · 27 Apr 2002 · Shift 1
If a body loses half of its velocity on penetrating $3 cm$ in a wooden block, then how much will it penetrate more before coming to rest?
1. A. $1 cm$
2. B. $2 cm$
3. C. $3 cm$
4. D. $4 cm$
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Answer: A
Q782002 · 27 Apr 2002 · Shift 1
When forces $F_{1}, F_{2}, F_{3}$ are acting on a particle of mass $m$ such that $F_{2}$ and $F_{3}$ are mutually perpendicular, then the particle remains stationary. If the force $F_{1}$ is now removed then the acceleration of the particle is
1. A. $F_{1} / m$
2. B. $F_{2} F_{3} / m F_{1}$
3. C. $(F_{2} - F_{3}) / m$
4. D. $F_{2} / m$
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Answer: A
Q792002 · 27 Apr 2002 · Shift 1
Two forces are such that the sum of their magnitudes is $18 N$ and their resultant is $12 N$ which is perpendicular to the smaller force. Then the magnitudes of the forces are
1. A. $12 N, 6 N$
2. B. $13 N, 5 N$
3. C. $10 N, 8 N$
4. D. $16 N, 2 N$ .
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Answer: B
Q802002 · 27 Apr 2002 · Shift 1
Speeds of two identical cars are $u$ and $4 u$ at the specific instant. The ratio of the respective distances in which the two cars are stopped from that instant is :
1. A. $1 : 1$
2. B. $1 : 4$
3. C. $1 : 8$
4. D. $1 : 16$
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Answer: D
Q912002 · 27 Apr 2002 · Shift 1
Energy required to move a body of mass $m$ from an orbit of radius $2 R$ to $3 R$ is
1. A. $\frac{GM m}{12 R ^{2}}$
2. B. $\frac{GM m}{3 R ^{2}}$
3. C. $\frac{GM m}{8 R}$
4. D. $\frac{GM m}{6 R}$
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Answer: D
Q952002 · 27 Apr 2002 · Shift 1
Heat given to a body which raises its temperature by $1^{\circ} C$ is
1. A.water equivalent
2. B.thermal capacity
3. C.specific heat
4. D.temperature gradient
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Answer: B
Q1002002 · 27 Apr 2002 · Shift 1
At what temperature is the $r . m . s$ velocity of a hydrogen molecule equal to that of an oxygen molecule at $4 7^{\circ} C$ ?
1. A. $80 K$
2. B. $- 73 K$
3. C. $3 K$
4. D. $20 K$
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Answer: D