SSC JE electrical question paper 2019 with solution SET-2

Answer.4. Electric flux

Explanation:-

⇒ The electric potential at a point is defined as the work done in bringing the unit positive charge ( +1C) from infinity to that point. The work done is independent of the path taken. Its unit is Volt (V).

⇒ Potential Difference (pd or V) is a measure of the difference in charge between two points in a conductor. Its unit is Volt (V).

⇒ The difference in charge produced by the battery is stored in the battery as electrical potential energy and is called electromotive force (shortened to emf). Electromotive force is also measured in volts. Its unit is Volt (V).

⇒ Electric flux is a measure of how much the electric field vectors penetrate through a given surface. The SI unit of electric flux is N.m²/C.

Electrical potential, Potential difference, Electromotive force has the same SI unit i.e Volt (V). Hence Electric flux is alike from others.

Answer.3. I_E > I_C > I_B

Explanation:-

The emitter current (I_E) of a transistor has two components such as base current (I_B) and collector current (I_C). The base current (I_B) is about 2% of the emitter current (I_E), but the collector current (I_a) is about 98% of the emitter current (I_E).

∴ I_E > I_C > I_B

I_E = I_B + I_C

Answer.2. 10/2π

Explanation:-

The strength of a magnetic field is specified by the magnetic induction B or by the magnetic field strength H. A current I through a long, straight wire produces a magnetic field with strength H = I/2πr at a distance r from the wire.

Given

H = 1 A/m

I = 10 A

H = I/2πr

1 = 10/2πr

r = 10/2π

Answer.4. The charge on each capacitor is the same and the same current flows through each capacitor in a given time

Explanation:-

When voltage is applied across the capacitor one plate becomes negatively charged with electrons leaving the battery. At the same time, electrons leave the other plate to resupply the battery, leaving that plate positively charged. This effect is called polarisation. The current flows until the charge across the capacitor is equal to the battery emf, at which point everything stops.

In series connections, the same charging current flows through all capacitors as soon as a voltage is applied. Hence in a series connection same current flows through each capacitor.

Answer.4. Eddy current heating

Explanation:-

High-frequency Heating

The main difference between the power-frequency and the high-frequency heating is that in the conventional methods, the heat is transferred either by conduction convection or by radiation. In the high-frequency heating methods, the electromagnetic energy is converted into the heat energy inside the material. An example of high-frequency heating is Induction heating and Eddy’s current heating

High-Frequency Eddy Current Heating

This type of heating is also one typical form of induction heating. Due to high-frequency currents, the conversion of electromechanical energy into heat takes place in the charge itself.

The high-frequency heating can be applied to two types of materials. The heating of the conducting materials, such as ferromagnetic and non-ferromagnetic, is known as induction heating. The process of heating of the insulating materials is known as dielectric heating. The coil is supplied with a supply of a very high frequency of the order of 10 kHz to 900 kHz. These currents at such a high frequency set up a magnetic field around the charge. Due to this eddy current gets induced in the charge.

Answer.3. Paramagnetic

Explanation:-

Atoms or ions with unpaired electrons are attracted to a magnetic field; the more unpaired electrons, the greater is the attraction. Such substances are called paramagnetic. Molecular oxygen is a paramagnetic gas by virtue of its two unpaired electrons.

Answer.4. Free-running period

Explanation:-

The speed-time curve of urban service is shown in the figure.

• In this service, there is no free-running period.
• The distance between the two stops is less about 1 km. Hence, relatively short coasting and longer braking period are required. The relative values of acceleration and retardation are high to achieve a moderately high average between the stops.
• The acceleration for the urban service lies between 1.6 and 4 km/h.
• The coasting retardation is about 0.15 km/p and the braking retardation is lying between 3 and 5 km/h.

Answer.4. Sag

Explanation:-

The difference in level between points of supports and the lowest point on the conductor is called sag.

1. When the conductor is suspended between two supports at some level, it takes the shape of a catenary. However, if the sag is very small compared with the span, then the sag-span curve is like a parabola.
2.  The tension at any point on the conductor acts tangentially. Thus tension T_o at the lowest point O acts horizontally.

Answer.3. 50 to 150 W

Explanation:-

The wattage rating for a ceiling fan motor is in the range of 50 to 150 W. if the ceiling Fans size ranges from 36 inches to 56 inches then the total wattage use is 55 to 100 watts.. A 48-inch ceiling fan will use 75 watts.

Answer.4. Stroboscopic effect

Explanation:-

The stroboscopic effect is a visual phenomenon that happens when a blinking light source glows an object in movement, generating a sequence of samples. The stroboscopic effect is based on Illuminance hence it is not related to the transmission and distribution of electric power.