MCQOPTIONS
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MCQOPTIONS
This section includes 778 Mcqs, each offering curated multiple-choice questions to sharpen your Physics Mcqs knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Semi-conductor germanium and silicon are_________________? |
| A. | pentavalent |
| B. | trivalent |
| C. | divalent |
| D. | tetravalent |
| Answer» E. | |
| 252. |
Many of the semi conductors are crystals of the type__________________? |
| A. | Face centred cubic |
| B. | Body centred cubic |
| C. | Simple cubic |
| D. | All of the above |
| Answer» B. Body centred cubic | |
| 253. |
In n-p-n transistor, p works as______________? |
| A. | collector |
| B. | emitter |
| C. | base |
| D. | any of above |
| Answer» D. any of above | |
| 254. |
p-n junction when reversed biased acts as a_______________? |
| A. | capacitor |
| B. | inductor |
| C. | on switch |
| D. | off switch |
| Answer» E. | |
| 255. |
Identify the correct statement about minority carriers_____________? |
| A. | holes in n-type and free electrons in p-type |
| B. | holes in n-type and p-type |
| C. | free electrons in n-type and holes in p-type |
| D. | free electrons in n-type and p-type |
| Answer» B. holes in n-type and p-type | |
| 256. |
The velocity of an oscillating charge as it moves to and fro along a wire is always_____________? |
| A. | constant |
| B. | zero |
| C. | changing |
| D. | infinite |
| Answer» D. infinite | |
| 257. |
Wave-like characteristic of electron is demonstrated by______________? |
| A. | Line spectrum of atoms |
| B. | Production of x-rays. |
| C. | Diffraction by crystalline solids |
| D. | Photoelectric effect |
| Answer» D. Photoelectric effect | |
| 258. |
An electron enters a region where the electric field E is perpendicular to the magnetic field B. It will suffer no deflection if_________________? |
| A. | E = BeV |
| B. | B = eE/V |
| C. | E = BV |
| D. | E = BeV/2 |
| Answer» D. E = BeV/2 | |
| 259. |
The standard vector symbol for flux density is ____________________? |
| A. | M |
| B. | L |
| C. | H |
| D. | B |
| Answer» C. H | |
| 260. |
An instrument which can measure potential without drawing any current is_____________________? |
| A. | voltmeter |
| B. | galvanometer |
| C. | cathode ray oscilloscope (CRO) |
| D. | ammeter |
| Answer» D. ammeter | |
| 261. |
When the coil of the galvanometer is in equilibrium then the deflecting couple is____________________? |
| A. | zero |
| B. | equal to the restoring couple |
| C. | greater than the restoring couple |
| D. | smaller than the restoring couple |
| Answer» C. greater than the restoring couple | |
| 262. |
Which one of the following is not an electromechanical instrument ? |
| A. | galvanometer |
| B. | voltmeter |
| C. | ammeter |
| D. | AC transformer and DC generator |
| Answer» E. | |
| 263. |
In a multi range ammeter as the range increases _____________________? |
| A. | shunt value decreases |
| B. | shunt value increases |
| C. | shunt value remains the same |
| D. | none of the above |
| Answer» B. shunt value increases | |
| 264. |
Maximum frequency in the spectrum from X-ray tube is directly proportional to the______________? |
| A. | Number of incident electron i.e. filament current |
| B. | The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated |
| C. | The soft target which can easily emit electrons |
| D. | All of above are correct |
| Answer» C. The soft target which can easily emit electrons | |
| 265. |
The value of resistivity for insulator is of the order of____________? |
| A. | 105 ohm metre |
| B. | 106 ohm metre |
| C. | 107 ohm metre |
| D. | 108 ohm metre |
| Answer» E. | |
| 266. |
X-rays are diffracted by a crystal but not by a diffraction grating because_____________? |
| A. | The ions in a crystal are well arranged |
| B. | The lines in a diffraction grating cannot reflect X-rays. |
| C. | The penetration power of X-rays is high in a diffraction grating |
| D. | The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal |
| Answer» E. | |
| 267. |
A current carrying conductor is placed in a uniform magnetic field parallel to it. The magnetic force experienced by the conductor is _____________________? |
| A. | F=1/B |
| B. | F=1/Bsinθ |
| C. | F/0 |
| D. | F=1/Bcosθ |
| Answer» D. F=1/Bcosθ | |
| 268. |
In normal state of energy the incident high energy photons will be______________? |
| A. | Stimulated |
| B. | Absorbed |
| C. | Cause X-ray emission |
| D. | Cause laser production |
| Answer» C. Cause X-ray emission | |
| 269. |
Electron cannot exist in the nucleus it is confirmed by observing that______________? |
| A. | It does emit radiation |
| B. | Its size as compare to proton and neutron is very small |
| C. | No antiparticle of electron is present |
| D. | The velocity of electron must be very high according to uncertainty principle |
| Answer» E. | |
| 270. |
In laser production the state in which more atoms are in the upper state than in the lower one is called_____________? |
| A. | Metal stable state |
| B. | Normal state |
| C. | Inverted population |
| D. | All the above |
| Answer» D. All the above | |
| 271. |
In He-Ne laser the lasing action is produced by_______________? |
| A. | Ne only |
| B. | He-Ne both |
| C. | Electrons of He |
| D. | Electrons Ne |
| Answer» B. He-Ne both | |
| 272. |
The metastable state for an atom in laser light is_____________? |
| A. | 10-4 sec |
| B. | 10-5 sec |
| C. | 10-3 sec |
| D. | 10-8 sec |
| Answer» D. 10-8 sec | |
| 273. |
When a body is whirled in a horizontal circle by means of a string the centripetal force is supplied by______________? |
| A. | Mass of a body |
| B. | Velocity of body |
| C. | The tension in the string |
| D. | Centripetal acceleration |
| Answer» D. Centripetal acceleration | |
| 274. |
Centripetal force performs_______________? |
| A. | Maximum work |
| B. | Minimum work |
| C. | Negative work |
| D. | No work |
| Answer» E. | |
| 275. |
Coil of a galvanometer is suspended in a radial magnetic field so that the deflecting torque on the coil is always___________________? |
| A. | BINA cosa |
| B. | BINA sina |
| C. | BINA tana |
| D. | BINA |
| Answer» E. | |
| 276. |
A particle of mass m charge q and speed V enters a uniform magnetic radius r. The radius r of the circle is_________________? |
| A. | independent mass m |
| B. | directly proportional to m |
| C. | directly proportional to q |
| D. | directly proportional to B |
| Answer» E. | |
| 277. |
Radiation with wavelength longer than red lights______________? |
| A. | ultraviolet rays |
| B. | X-rays |
| C. | infra red radiation |
| D. | visible radiation |
| Answer» D. visible radiation | |
| 278. |
If a current carrying solenoid is suspended freely it will__________________? |
| A. | be rotating |
| B. | come to rest in N-S direction |
| C. | vibrating like galvanometer needle |
| D. | comes to rest after rotation |
| Answer» C. vibrating like galvanometer needle | |
| 279. |
When a particle of charge q and mass m enters into a uniform magnetic field B moving with a velocity v perpendicular to the direction for the field it describes a circular path of radius___________________? |
| A. | R=qB/mV |
| B. | R=mV/qB |
| C. | R=qmV/B |
| D. | R=qmB/V |
| Answer» C. R=qmV/B | |
| 280. |
A magnetic compass will be deflected if it is kept near a____________________? |
| A. | charge in motion |
| B. | charge at rest |
| C. | both |
| D. | none |
| Answer» B. charge at rest | |
| 281. |
X-rays are similar in nature to_______________? |
| A. | Cathode rays |
| B. | Positive rays |
| C. | γ-rays |
| D. | Beta rays |
| Answer» D. Beta rays | |
| 282. |
Thermions are________________? |
| A. | protons |
| B. | positrons |
| C. | electrons |
| D. | photons |
| Answer» D. photons | |
| 283. |
In an electronic transition atom cannot emit______________? |
| A. | γ-rays |
| B. | Infra red radiation |
| C. | Visible light |
| D. | Ultraviolet rays |
| Answer» B. Infra red radiation | |
| 284. |
Quality of X-rays depends upon ____________ A-filament current B-accelerating voltage C-material of the target ? |
| A. | A & B |
| B. | B & C |
| C. | A & C |
| D. | A B & C |
| Answer» C. A & C | |
| 285. |
The effective way to increase the sensitivity of a moving coil galvanometer is to___________________? |
| A. | use a very long and fine suspension |
| B. | use a coil of very large area |
| C. | use a coil with very large number of turns |
| D. | use a very strong magnetic field |
| Answer» E. | |
| 286. |
While measuring the unknown resistance the help of slide wire bridge a greatest accuracy can be achieved when__________________? |
| A. | a most sensitive galvanometer is used |
| B. | a steady voltage cell is used |
| C. | the balance point is close to the middle of the wire |
| D. | a high resistance box is used in one of its gap |
| Answer» D. a high resistance box is used in one of its gap | |
| 287. |
The deflection for 50 division of galvanometer is decreased to 25 divisions by shunt resistance of 12Ω. Galvanometer resistance is_____________? |
| A. | 18Ω |
| B. | 30Ω |
| C. | 24Ω |
| D. | 12Ω |
| Answer» E. | |
| 288. |
The minimum wavelength of X-rays can further be reduced by _______________? |
| A. | Reducing the pressure or cooling the target |
| B. | Increasing the temperature of the filament |
| C. | Using a target element of higher atomic number |
| D. | Increasing the potential difference between the cathode and the target |
| Answer» E. | |
| 289. |
In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is_______________? |
| A. | he/ev |
| B. | he/Vc |
| C. | eV/h |
| D. | impossible to predict |
| Answer» B. he/Vc | |
| 290. |
Radiation produced from TV picture tube is_____________? |
| A. | B-rays |
| B. | X-rays |
| C. | Far infrared |
| D. | Infrared |
| Answer» C. Far infrared | |
| 291. |
The number of categories in which physical quantities are divided is_____________? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 292. |
An ammeter measures the total current flowing through a circuit when it is connected__________________? |
| A. | in series with the circuit |
| B. | in parallel with circuit |
| C. | in series with any of the parallel resistances in the circuit |
| D. | in parallel with any of the series resistances in the circuit |
| Answer» B. in parallel with circuit | |
| 293. |
The radiations emitted form hydrogen filled discharge tube show____________? |
| A. | band spectrum |
| B. | line spectrum |
| C. | continuous spectrum |
| D. | absorption spectrum |
| Answer» C. continuous spectrum | |
| 294. |
Galvanometer is a very sensitive device with______________________? |
| A. | very low damping |
| B. | very high damping |
| C. | no damping at all |
| D. | radial field disintegration |
| Answer» B. very high damping | |
| 295. |
When an electron moving with a uniform speed in a vacuum enters a magnetic field in a direction perpendicular to the field the subsequent path of the electron is ___________________? |
| A. | a straight line parallel to the field |
| B. | a parabola in a plane perpendicular to the field |
| C. | a circle in a plane perpendicular to the field |
| D. | a straight line along its initial direction |
| Answer» D. a straight line along its initial direction | |
| 296. |
In hydrogen spectrum which one of the following series lies in the ultraviolet region ? |
| A. | Balmer series |
| B. | Pfund series |
| C. | Bracket series |
| D. | Lymann series |
| Answer» E. | |
| 297. |
Magnetic flux and flux density are related by___________________? |
| A. | magnetic flux = flux density / area |
| B. | magnetic flux = flux density x area |
| C. | flux density = magnetic flux area |
| D. | flux density = magnetic flux x area |
| Answer» C. flux density = magnetic flux area | |
| 298. |
Bracket series is obtained when all transition of electron terminate on_______________? |
| A. | 4th orbit |
| B. | 5th orbit |
| C. | 3rd orbit |
| D. | 2nd orbit |
| Answer» B. 5th orbit | |
| 299. |
Photon of highest frequency will be absorbed when transition takes place from_____________? |
| A. | 1st to 5th orbit |
| B. | 2nd to 5th orbit |
| C. | 3rd to 5th orbit |
| D. | 4th to 5th orbit |
| Answer» B. 2nd to 5th orbit | |
| 300. |
When we excite some atoms by heat collision or electrical discharge they will________________? |
| A. | radiate electromagnetic energy with a continuous distribution of wavelength |
| B. | absorb particular wavelengths when white light is incident on them |
| C. | radiate electromagnetic energy of discrete characteristic wavelength |
| D. | emit either invisible or visible light |
| Answer» D. emit either invisible or visible light | |