General Electrical Engineering Questions – 2/B

(11) Inside a hollow conducting sphere

· electric field is zero.

· electric field is a non zero constant.

· electric field changes with magnitude of the charge given to the conductor.

· electric field changes with distance from the center of the sphere.

For any conducting sphere, the charge enclosed is zero hence the electric field inside it is zero.

(12) Two infinite parallel metal plates are charged with equal surface charge density of the same polarity. The electric field in the gap between the plates is

· same as that produced by one plate.

· double the field produced by one plate.

· dependent on coordinates of field points.

· zero.

The equal surface charge densities are having same charge either positive or negative. So, same charge repels each other. Hence, the resultant electric field in the gap between the plates is zero.

(13)As a result of reflection from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater than the velocity of light in space. This is called the

· velocity of propagation.

· normal velocity.

· group velocity.

· phase velocity.

The phase velocity of a wave is the rate at which the phase of the wave propagates in space. This is the speed at which the phase of any one frequency component of the wave travels. Basically, the speed of this velocity is greater than the velocity of light in space.

(14) Length of the cable is doubled, its capacitance C will be

· one-fourth.

· one-half.

· double.

· unchanged.

The length of the cable and the capacitance of the cable are directly proportional to each other. Hence, if the length gets doubled, then the capacitance also can be doubled.

(15) ————- is the most detrimental impurity in the magnetic materials

· Carbon.

· Sulphur.

· Oxygen.

· Nitrogen.

The carbon material is the harmful material than the other materials. That is why the carbon is the most detrimental impurity in the magnetic materials. Because of this reason, the amount of carbon in commercial magnetic material is added as low as 0.01 percent.

(16)The chemical effect of current is used in

· D.C ampere hour meter.

· D.C ammeter.

· D.C energy meter.

· none of the above.

The battery is rated in terms of ampere hour. The chemical effect of current is created by the batteries. Hence, the DC ampere hour meter is used to measure the ampere hour rating of the battery.

(17) Swamping resistance is used to compensate

· error due to temperature true variations.

· compensate error due to strong magnetic field.

· both A and B.

· none of these.

Swamping resistance is connected in series with the meter and that resistance has a negligible resistance co-efficient in order to reduce temperature errors in shunted ammeters.

(18) ———– was the first city in India to adopt electric traction.

· Delhi.

· Madras.

· Calcutta.

· Bombay.

Electric traction was introduced on Indian Railways in the year 1925 on 1.5 KV DC and the first electric train ran between Bombay’s Victoria Terminus and Kurla along the Harbour Line on February 3rd 1925. The total distance of 9.5 miles and that was flagged off by the Governor of Bombay “Sir Leslie Orme Wilson”.

(19)Unit of deflection sensitivity of a CRO is

· V / mm.

· meter / volt.

· mm per mV.

· mm / V.

The deflection sensitivity is actually the voltage required to transfer the electronic beam through a unit of length. So, the unit of deflection sensitivity if meter/volt.

(20) Null type recorders are

· bridge recorders.

· LVDT recorders.

· potentiometric recorder.

· any one of the above.

The recorders based on the working principle of self balancing or null conditions are called as the potentiometric recorders.