Magnetic Circuits Short Mcq Questions Answers

Magnetic Circuits Short Mcq Questions Answers

Magnetic Circuits Important Terms

1. Magnetomotive Force (m.m.f): It is magnetic pressure which sets up or tends to set up flux in a magnetic circuit. When electric current is passed through a winding wound  on a core, a magnetic field is produced in the core. The product of current and number of turns of the coil is equal to m.m.f.

m.m.f = N I Ampere-turns (AT)

Adding turns of wire to a coil has the same effect as increasing the current flow. For Example, a one-turn coil with 1 A of current flowing in it produces the same m.m.f as a 10-turn coil with only 0.1 A of current flow. Therefore, effective m.m.f. of a magnetic circuit is equal to the product of the number of turns and current.

Capacitance MCQ Short QUESTIONS ANSWERS Part 2

 CAPACITANCE  MCQ Short QUESTIONS ANSWERS Part 2

Any conducting object connected to earth is said to be grounded. Explain :

The earth is an electron source or sinks and is arbitrarily said to be zero potential. A conducting body connected to earth is also at zero potential or ground potential. Alternatively, the capacitance of the earth is so large that removal of electrons from it or supply of electrons to it makes no difference either in the charge or potential of earth.

Capacitance MCQ Short QUESTIONS ANSWERS Part 1

     CAPACITANCE MCQ Short QUESTIONS ANSWERS 4 Job University Admission Test

• The two charged conductors are touched mutually and then separated. What will be the charge on them?

              The charge on them will be divided in the ratio of their capacitances. We know that q= CV.

              When the charged conductors touch, they acquire the same potential. Hence q∞ C 

• The plates of a charged capacitor are connected to a voltmeter. If the plates of the capacitor are separated further, what will be the effect on the reading of the voltmeter?

                             V= q/C and C= €0 A/d

            As the capacitor plates are separated, C decreases. Since charge on the plates remains the  

            same, value of V increases. Hence, the reading of the voltmeter will increase.

Capacitance MCQ Short QUESTIONS ANSWERS

CAPACITANCE MCQ Short QUESTIONS ANSWERS

CAPACITOR

A capacitor is a device that is capable of storing charge. It essentially consists of two conducting surfaces separated by an insulating material. The conducting surfaces are called plates of the capacitor and the insulating material is called dielectric. The most commonly used dielectrics are air, mica, paper etc.

• A capacitor is generally named after the dielectric used. Example air capacitor, mica capacitor, paper capacitor etc.

• The capacitor may be in the form of parallel plates, concentric cylinders or other arrangement.

Electrostatics MCQ QUESTIONS ANSWERS eee Part1

Electrostatics MCQ  JOBS STUDY Engineering UNIVERSITY ADMISSION TEST QUESTIONS ANSWERS Part1

• The force between two electrons separated by a distance r varies as  r^-2.

• Two charges are placed at a certain distance apart. A brass sheet is placed between them. The force between them will decrease.

• Study under electrostatics lightning rod.

• The relative permittivity of air is 1 (one).

• The relative permittivity of a material is 10. Its absolute permittivity will be 8.854x10^-11 F/m.

• Another name for relative permittivity is dielectric constant.

• The relative permittivity of most materials lies between 1 and 10.

• When the relative permittivity of the medium is increased, the force between thwo charges placed at a given distance apart decreases.

• Two charges are placed at a distance apart. If a glass slab is placed between them, the force between the charges will decreases.

• A soap bubble is given a negative charge. Its radius Increases.