physics Mcqs
251. When the speed of a moving body is doubled then___________________?
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A. its P.E is doubled

B. its acceleration is doubled

C. its K.E is doubled

D. its momentum is doubled
252. On the basis of band theory of solids the semiconductors have _____________________?
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A. A partly filled valence band a totally empty conduction band and a wide forbidden band

B. A party filled valence band and totally empty conduction band

C. A completely filled valence band a totally empty conduction band and a very wide forbidden band

D. A completely filled valence band a partially filled conduction band and a narrow forbidden band
253. If east, west, north, south, up and down are representing the direction of unit vectors, then east x south has the direction along_____________?
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A. Up

B. North

C. West

D. Down
254. A magnetic compass will be deflected if it is kept near a____________________?
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A. none

B. charge at rest

C. both

D. charge in motion
255. Transuranic elements have an atomic number_______________?
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A. Greater than 72

B. Greater than 82

C. Greater than 102

D. Greater than 92
256. The effective way to increase the sensitivity of a moving coil galvanometer is to___________________?
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A. use a very long and fine suspension

B. use a very strong magnetic field

C. use a coil with very large number of turns

D. use a coil of very large area

257. SI unit of torque is______________?
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A. N.m

B. joule

C. Both a and b are correct

D. Neither a nor b is correct

258. X-rays are electromagnetic waves like________________?
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A. Microwaves

B. Light waves

C. ?-rays

D. Heat waves

259. Why gamma rays are used to kill bacteria to sterilize surgical equipment etc ?
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A. Chargeless

B. All of above

C. Massless

D. Highly penetrating
260. Strontium-90 is used as __________________?
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A. ?-particle source

B. Neutron source

C. ?-particle source

D. ?-rays source

261. pure resistor circuit the voltage and current are_______________?
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A. Lagging each other

B. They are at 90? phase difference

C. No phase difference

D. They have zero phase difference
262. CFC is used in _________________?
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A. Aerosol spray

B. Refrigeration

C. All of above

D. Plastic foam industry

263. When arrow is released form its bow, its energy is transformed from _____________________?
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A. heat energy to K.E

B. elastic P.E to K.E

C. K.E to elastic P.E.

D. elemical energy to elastic P.E

264. An angle between two vectors A and B can be determined by_____________?
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A. Their dot product

B. Head to tail rule

C. Their cross product

D. Right-hand rule

265. Work has the dimension as that of same as that of__________________?
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A. torque

B. power

C. linear momentum

D. angular momentum

266. Materials in which valence electrons are tightly bound to their atoms at low temperature are called___________________?
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A. Super conductors

B. Insulators

C. Conductor

D. Semi conductor

267. Mass of neutron is________________?
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A. 1.67 x 10-27 kg

B. 9.1 x 10-31 kg

C. 1.67 x 10-31 kg

D. 1.67 x 10-19 kg

268. At resonance the value of the power factor in an L-C-R series circuit is_______________?
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A. 1

B. Not definite

C. 2

D. Zero

269. The net charge on n-type material is____________________?
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A. Positive

B. Negative

C. Both positive and negative

D. Neutral
270. The charge on alpha particles is________________?
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A. Plus one

B. Minus two

C. Plus two

D. Minus one

271. If A=Ax i^ + Ay j^ + Az K^ B = Bx i^ + By j^ + Bz K^ then______________?
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A. A. B = Ay Bz + Az By + Az Bx

B. A. B = Ax By + Ay Bz + Az By

C. A. B = Ax Bz + Ay By + Az Bx

D. A. B = Ax Bx + Ay By + Az Bz
272. The magnetic field strength of solenoid is__________________?
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A. B = ?NI

B. B = ?N/I

C. B = ?nI

D. Both B and C
273. A voltage V = V0 cos ?t is applied across a resistor of resistance R the average power dissipated per cycle in the resistor is given by___________?
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A. 2/?2?R

B. V/?2?R

C. V02/?2R

D. V?/?2R

274. Electromagnetic waves travel in free space with the speed of___________________?
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A. More than sound waves

B. Positive rays

C. ?-rays

D. Cathode rays

275. Average distance covered by alpha particles in the air before its ionizing power ceases is called its_________________?
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A. Range

B. Firing level

C. Limit

D. Trajectory

276. The relation between horse power and watt is_________________?
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A. 1 hp = 546 watts

B. 1 hp = 946 watts

C. 1 hp = 746 watts

D. 1 hp = 1000 watts

277. A wire of length L is stretched by a length E when a force F is applied at one end. If the elastic limit is not exceeded the amount of energy stored in the wire is_________________?
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A. FE2/L

B. FE

C. FE2

D. (FE)
278. The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12?. Galvanometer resistance is_____________?
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A. 30?

B. 24?

C. 12?

D. 18?

279. The sensitivity of a galvanometer is given by__________________?
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A. BAN/C

B. ABC/N

C. CAN/B

D. C/BAN
280. The consumption of energy by a 60 watt bulb in 2 sec is_________________?
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A. 60 J

B. 0.02 J

C. 120 J

D. 30 J

281. Choose the correct statement. In the case of AC circuit ohms law holds for_______________?
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A. Instantaneous values of voltage and current

B. All of the above

C. Peak values of voltage and current

D. Effective values of voltage and current

282. An elevator weighing 3.5 x 10-6 N is raised to a height of 1000 m in the absence of friction, the work done is_________________?
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A. 3.5 x 104 J

B. 3.5 x 103 J

C. 3.5 x 106 J

D. 3.5 x 109 J
283. A central force is that which__________________?
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A. Cannot produce torque

B. Can produce torque

C. Has no relation with torque

D. Some time can produce torque some time cannot

284. Pair production cannot take place in a vacuum as ________ is not conserved ?
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A. MomentumB.

B. Energy

C. Charge

D. Mass

285. Gravitational P.E of a body has____________________?
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A. a formula

B. no general formula

C. a formula mgh only

D. no formula

286. The ration stress to strain in youngs modulus of the material then tension is__________________?
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A. Inversely proportional to extension

B. Directly proportional to strain

C. Directly proportional to extension

D. Directly proportional to square of amplitude

287. One AMU is equal to__________________?
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A. 1.66 x 10-27kg

B. All of above

C. 166 x 10-15ng

D. 166 x 10-20g

288. To find the r.m.s value of an alternating current mathematically we need to have ________________?
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A. Square root of mean value of I2

B. Square root of I2

C. Mean value of I2

D. Square of 1/2

289. A vector can be multiplied by a number. The number may be_______________?
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A. Negative

B. Dimensional scalar

C. Dimensionless

D. All A, B and C are correct
290. A vacant or partially filled band is called _____________________?
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A. Empty band

B. Conduction band

C. Valence band

D. Forbidden band

291. The path of alpha particle is_______________?
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A. Rectilinear

B. Curved

C. Elliptical

D. Zig-zag or erratic
292. According to which one of following law the density of atom is uniform ?
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A. J.J.Thomson model

B. All of the above laws contradict the statement

C. Bohrs model

D. Rutherfords model

293. Holes can exist in____________________?
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A. Conductors

B. Insulators

C. All of the above

D. Semi conductors
294. A wire of resistance R is coiled inductively so that its inductance is L. The impedance of the coil at a frequency of f is_______________?
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A. (R2+f2L2)

B. (R+2?fL)

C. (R2+4?2f2L2)

D. R+1/2?fL

295. Value of permeability of free space in SI units is___________________?
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A. 4?x10-7 WbA-1m-1

B. 4?x10-8 WbA-1m-1

C. 4?x10-9 WbA-1m-1

D. 4?x10-10 WbA-1m-1

296. An electromagnetic wave consists of _____________________?
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A. Electric and magnetic fields moving perpendicular to each other

B. Magnetic field moving with velocity of light in space

C. Electric field moving with velocity of light

D. Electric and magnetic fields moving parallel to each other

297. The direction of the vector product is given by______________?
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A. Head to tail rule

B. Left-hand rule

C. Right-hand rule

D. Triangular rule

298. Nuclear forces exist between ___________________?
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A. All of the above

B. Proton-proton

C. Neutron-neutron

D. Proton-neutron

299. Energy needed to magnetize and demagnetize is represented by _________________?
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A. Straight line

B. Hysteresis curve

C. Hysteresis loop area

D. Hysteresis loop

300. Biomass can be converted into fuels by____________________?
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A. direct combustion

B. fermentation

C. both A and B

D. none of these