Q1451. Photon is the fundamental unit/ quantum of
(a) gravitation (b) electricity
(c) magnetism (d) light
Ans: (d)
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Q1452. The term reactor referred to in waste water treatment is
(a) Vessel (b) Settling tank
(c) Clarifier (d) Aeration tank
Ans: (d)
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Q1453. Which of the following supports particle nature of photons ?
(a) Diffraction (b) Polarization
(c) Photoelectric effect
(d) Interference
Ans: (c)
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Q1454. Which of the following is not caused by atmospheric refraction of light ?
(a) Sun appearing red at sunset
(b) Twinkling of stars at night
(c) Sun appearing higher in the sky than it actually is
(d) Sun becoming visible two or three minutes before actual sunrise
Ans: (c)
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Q1455. A man standing on a edge of a cliff throws a stone vertically upwards with a certain speed. He then throws another stone downwards with the same speed. Find the ratio of the speeds of the two stones when they hit the ground.
(a) 1 : 1
(b) 1 : 2
(c) 1 : 4
(d) Cannot be found from the given information.
Ans: (a)
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Q1456. A white and smooth surface is
(a) good absorber and good reflector of heat
(b) bad absorber and good reflector of heat
(c) good absorber and bad reflector of heat
(d) bad absorber and bad reflector of heat
Ans: (b)
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Q1457. Ohm’s law is valid in case of
(a) semiconductor
(b) conductor
(c) superconductor
(d) insulator
Ans: (b)
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Q1458. Rocket works on the principle of
(a) Newton’s Third Law
(b) Newton’s First Law
(c) Newton’s Second Law
(d) Archimedes Principle
Ans: (a)
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Q1459. An object which absorbs all colours and reflects none appears:
(a) white (b) grey
(c) blue (d) black
Ans: (d)
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Q1460. Which one among the following doesn’t have any effect on velocity of sound ?
(a) Pressure
(b) Temperature
(c) Humidity
(d) Density
Ans: (c)
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Q1461. If the phase difference between two points is 120° for a wave with velocity of 360 m/ and frequency 500 Hz, then path difference between the two points is
(a) 1 cm (b) 6 cm
(c) 12 cm (d) 24 cm
Ans: (d)
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Q1462. The damage of the human body due to radiation (X-rays or rays etc,) is measured in :
(a) Rems (b) Roentgen
(c) Curie (d) Rads
Ans: (a)
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Q1463. The unit of noise pollution (level) is :
(a) decibel (b) decimal
(c) ppm (d) None of these
Ans: (a)
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Q1464. The motion of the wheels of a bullock-cart while moving on the road is an example of
(a) Oscillatory and rotatory motion
(b) Oscillatory and translatory motion
(c) Translatory and rotatory motion
(d) Translatory motion only
Ans: (c)
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Q1465. Stationary wave is formed by
(a) a transverse wave superposing a longitudinal wave
(b) two waves of the same speed superposing
(c) two waves of same frequency travelling in the same direction
(d) two waves of same frequency travelling in the opposite direction
Ans: (d)
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Q1466. A needle or a pin floats on the surface of water because of
(a) Surface tension
(b) Surface energy
(c) Viscosity
(d) Adhesive force
Ans: (a)
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Q1467. In a conductor
(a) there is no conduction band
(b) the forbidden energy gap is very wide
(c) the forbidden energy gap is very narrow
(d) the valence band and the conduction band overlap each other
Ans: (d)
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Q1468. The colours of stars depend on their
(a) temperature
(b) distance
(c) radius
(d) atmospheric pressure
Ans: (a)
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Q1469. In which one of the following the phenomenon of total internal reflection of light is used ?
(a) Formation of mirage
(b) Working of binoculars
(c) Formation of rainbow
(d) Twinkling of stars
Ans: (c)
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Q1470. The word ‘insolation’ means
(a) matters which insulate
(b) incoming solar radiation
(c) insoluble matters
(d) None of the above
Ans: (b)
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Q1471. Which of these waves can be polarized ?
(a) Sound waves in air
(b) Longitudinal waves on a string
(c) Transverse waves on a string
(d) Light waves
Ans: (d)
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Q1472. An object covers distance which is directly proportional to the square of the time. Its accelaration is
(a) increasing (b) decreasing
(c) zero (d) constant
Ans: (d)
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Q1473. Which of the following have the same unit ?
(a) Work and power
(b) Torque and moment of inertia
(c) Work and torque
(d) Torque and angular momentum
Ans: (c)
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Q1474. A man standing at the top of a tower has two spheres A and B.
He drops sphere A downwards and throws sphere B horizontally at the same time. Which of the following is correct ?
(a) Both the spheres will reach the ground simultaneously.
(b) A will reach the ground first.
(c) B will reach the ground first.
(d) The question is incomplete because the masses of the spheres are not given.
Ans: (a)
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Q1475. Water has maximum density at
(a) 100°C (b) 0°C
(c) 4°C (d) 273°C
Ans: (c)
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Q1476. Which of the following is not a vector quantity ?
(a) Speed (b) Velocity
(c) Torque (d) Displacement
Ans: (a)
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Q1477. An electron microscope gives higher magnifications than an optical microscope because :
(a) The velocity of electrons is smaller than that of light
(b) The wavelength of electrons is smaller as compared to the wavelength of visible light
(c) The electrons have more energy than the light particulars
(d) The electron microscope uses more powerful lenses
Ans: (b)
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Q1478. Vehicles use _____ to see the objects coming from behind.
(a) Concave lens
(b) Convex lens
(c) Convex mirror
(d) Concave mirror
Ans: (b)
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Q1479. The Dynamo converts
(a) Electrical Energy into Mechanical Energy
(b) Mechanical Energy into Magnetic Energy
(c) None of these
(d) Mechanical Energy into Electrical Energy
Ans: (d)
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Q1480. The purpose of choke in a fluorescent lamp is :
(a) to increase the current flow
(b) to decrease the current flow
(c) to decrease the resistance
(d) ro decrease the voltage momentarily
Ans: (b)