Multiple Choice Questions Topic Outline
- MCQs in Atomic Structure
- MCQs in Electric Charge
- MCQs in Ohm's Law, Kirchoff Law, Coulomb's Law, etc
- MCQs in Magnetic Power
- MCQs in Magnetic Field and Magnetic Flux
- MCQs in Magnetic and Electric Quantities / Units
- MCQs in Magnetic/Electromagnet Principles
The Six-Parts Series
Following is the list of multiple choice questions in this brand new series:
Start with Part VI of the MCQs Series
251. The relation between absolute permittivity of air (ε0), absolute permeability of air (μ0) and velocity of light (c) is given by
- A. μ0ε0 = c2
- B. μ0ε0 = c
- C. 1/μ0ε0 = c
- D. 1/μ0ε0 = c2
252. The dielectric constant of most materials lies between
- A. 1 and 10
- B. 10 and 20
- C. 20 and 50
- D. 50 and 100
253. A test charge means a charge of
- A. -1 C
- B. 1 electron
- C. +1 C
- D. -20 C
254. Electric lines of force leave or enter the charge surface at an angle of
- A. 30o
- B. 45 o
- C. 90 o
- D. depending upon the angle of launch and entry
255. Electric field intensity is measured in
- A. volts/meter
- B. Newton/meter
- C. Newton-meter
- D. Amperes/meter
256. Electric field intensity is a ________.
- A. scalar
- B. phasor
- C. vector
- D. variable
257. Electric field intensity at a point due to a given charge ______ if the relative permittivity of the medium decreases.
- A. decreases
- B. remains unchanged
- C. increases
- D. becomes zero
258. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the plates, then electric field intensity will be
- A. 20 N/C
- B. 100 N/C
- C. 4 N/C
- D. 40 N/C
259. The electric flux density is a ________ quantity.
- A. phasor
- B. vector
- C. scalar
- D. variable
260. The permittivity of a material is given by one of the following formulas.
- A. DE
- B. E/D
- C. D^2/E
- D. D/E
261. Electric field intensity at a point is numerically equal to ________ at that point.
- A. potential gradient
- B. potential difference
- C. dielectric constant
- D. the force
262. Three charges of +5 C, -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
- A. 8 C
- B. 14 C
- C. 20 C
- D. -6 C
263. The potential at a point due to a charge is 15 V. If the distance is increased three times, the potential at the point will be
- A. 5 V
- B. 18 V
- C. 45 V
- D. 15 V
264. Electric potential is a _______ quantity.
- A. scalar
- B. phasor
- C. vector
- D. variable
265. The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3, then electric potential at that point will be
- A. 63 V
- B. 21 V
- C. 7 V
- D. 42 V
266. The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 C moves from A to B, then energy released as
- A. 5 joules
- B. 25 joules
- C. 10 joules
- D. 100 joules
267. What is the other name for dielectric strength?
- A. Breakdown voltage
- B. Electric intensity
- C. Potential gradient
- D. Dielectric constant
268. Which of the following materials has the highest dielectric strength?
- A. Glass
- B. Oiled paper
- C. Mica
- D. Air
269. What is used as the insulating material or dielectric in an electric ion?
- A. Oiled paper
- B. Mica
- C. Paraffin
- D. Titanate compound
270. What is used as the dielectric material in high voltage transformers?
- A. Mica
- B. Paraffin
- C. Porcelain
- D. Oiled paper
271. One farad equals
- A. 1 coulomb/volt
- B. 1 newton/coulomb
- C. 1 newton-meter
- D. 1 volt/second/ampere
272. Which of the following is used by permanent magnets as the magnetic material?
- A. iron
- B. nickel
- C. soft steel
- D. hardened steel
273. Which of the following is used by temporary magnets as the magnetic material?
- A. Hardened steel
- B. Cobalt steel
- C. Soft iron
- D. Tungsten steel
274. What is the main advantage of temporary magnets?
- A. The magnetic flux can be changed.
- B. Hysteresis can be decreased.
- C. Magnetic materials can be used.
- D. Abundance of ferromagnetic material that can be temporarily magnetized.
275. Permanent magnets can be found in
- A. electric bells
- B. earphones
- C. relays
- D. dynamic loudspeakers
276. Temporary magnets are commonly employed in
- A. electric instruments
- B. motors
- C. moving coils loudspeakers
- D. magnetos
277. The force between two magnetic poles is _______ their pole strengths.
- A. directly proportional to
- B. the sum of
- C. inversely proportional to
- D. the product of
278. If the distance between two magnetic poles decreases by 2 times, the force between them
- A. decreases two times
- B. increases four times
- C. increases two times
- D. decreases four times
279. The force between two magnetic poles is _____ the relative permeability of the medium.
- A. directly proportional to
- B. independent of
- C. inversely proportional to
- D. equal to
280. Two similar poles, each 1Wb, placed 1 m apart in air will experience a repulsive force of
- A. 63000 N
- B. 63 × 10^-3 N
- C. 8 × 10^12 N
- D. 796 kN
281. One weber of flux is equal to _______ magnetic lines of force.
- A. 106
- B. 1010
- C. 4π × 107
- D. 108
282. The unit of flux density is
- A. Wb/m
- B. Tesla
- C. At/m
- D. N/Wb
283. What is the typical saturation flux density for most magnetic materials?
- A. 4 Wb/m2
- B. 5 Wb/m2
- C. 1 Wb/m2
- D. 2 Wb/m2
284. Magnetic field intensity is a ________ quantity.
- A. scalar
- B. phasor
- C. vector
- D. variable
285. The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?
- A. 5 N/Wb
- B. 25 N/Wb
- C. 125 N/Wb
- D. 0.2 N/Wb
286. The relative permeability of a magnetic material is 10^5. What is its permeability?
- A. 4π × 105 H/m
- B. 4π × 10-12 H/m
- C. 4π × 10-2 H/m
- D. 4π × 10-7 H/m
287. Which of the following has the highest permeability?
- A. Soft iron
- B. Steel
- C. Air
- D. Permalloy
288. A magnetic pole produces 5000 field lines. How much is the flux in webers?
- A. 50 × 10-6
- B. 5 × 10-6
- C. 500 × 10-6
- D. 500 × 10-5
289. As the magnetic intensity decreases, the relative permeability of a magnetic material
- A. decreases
- B. remains the same
- C. increases
- D. becomes zero
290. The permeability of a material having a flux density of 5 Wb/m^2 is 10^-5 H/m. What is the value of magnetizing force?
- A. 5 × 10-5 N/Wb
- B. 500 × 103 N/Wb
- C. 4π × 10-7 N/Wb
- D. 4π × 107 N/Wb
291. When the relative permeability of a material is slightly less than 1, it is called _____ material.
- A. diamagnetic
- B. ferromagnetic
- C. paramagnetic
- D. non-magnetic
292. When the relative permeability of a material is slightly more than 1, it is called ______ material.
- A. diamagnetic
- B. ferromagnetic
- C. paramagnetic
- D. non-magnetic
293. Which of the following is a diamagnetic material?
- A. Aluminum
- B. Silver
- C. Air
- D. Cobalt
294. Which of the following is a paramagnetic material?
- A. Carbon
- B. Bismuth
- C. Copper
- D. Oxygen
295. The greater percentage of materials is _________.
- A. diamagnetic
- B. paramagnetic
- C. ferromagnetic
- D. non-magnetic
296. When the relative permeability of a material is much greater than 1, it is called _______ material.
- A. diamagnetic
- B. ferromagnetic
- C. paramagnetic
- D. non-magnetic
297. The flux density in an air-cored coil is 10^-3 Wb/m^2. With a cast iron core of relative permeability 100 inserted, the flux density will become
- A. 10-3 Wb/m2
- B. 10-2 Wb/m2
- C. 103 Wb/m2
- D. 0.1 Wb/m2
298. At/m is a unit of
- A. mmf
- B. magnetic force
- C. reluctance
- D. magnetic flux density
299. The direction of force o a current carrying conductor placed in a magnetic field can be found by
- A. Cork screw rule
- B. Fleming’s left hand rule
- C. Fleming’s right hand rule
- D. using a compass
300. When a current carrying conductor is placed in a magnetic field, the maximum force will act on the conductor when the conductor is at an angle of _______ to the magnetic field.
- A. 45o
- B. 60o
- C. 30o
- D. 90o
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