Ques.110. Humans are more vulnerable to Electric shock current at? (SSC-2015)

50 Hz

48 Hz

45 Hz

40 Hz

Answer.4. 40 Hz

Explanation:-

Lower frequency AC is more dangerous than higher frequency AC because less frequency means less inductive reactance so high current.

Ques.111. An active element in the circuit is one (SSC-2015)

Dissipates energy

Receives Energy

Both receives and supplies

Supplies Energy

Answer.4. Supplies Energy

Explanation:-

The active elements generate energy. Batteries, generators, operational amplifiers etc are active elements.

Ques.112. The permissible voltage drop from the supply terminal to any point on the wiring system should not exceed? (SSC-2015)

2 % ± 1 volt

1% ± 1 volt

4% ± 1 volt

3% ± 1 volt

Answer.3. 4% ± 1 volt

Explanation:-

The permissible voltage drop from the supply terminal to any point on the wiring system should not exceed 4% ± 1 volt of the nominal supply voltage i.e for 230 V AC supply the permissible voltage drop is about 9.2 V.

Ques.113. If in an RLC series circuit, the frequency is below the resonant frequency, then (SSC-2015)

Xc < XL

Xc > XL

Xc = XL

None of the above

Answer.2. Xc > XL

Explanation:-

At resonance XL = Xc, the total circuit impedance is equal to circuit resistance i.e Z = R.

At the frequency below resonance frequency, the current leads the voltage because capacitive reactance is greater than the inductive reactance. i.e XL > Xc. So the circuit acts as the capacitive circuit.

Ques.114. If the power factor is high, then the consumer maximum demands (SSC-2015)

Increase

Decrease

Becomes zero

Remains Constant

Answer.2. Decrease

Explanation:- Kva=kw/cosθ

Now considering the above equation, for a given requirement of kW, the value of kVA reduces if we have a good power factor.

Let us understand with an example,

Consider a case wherein we need 100 kW as output. Now

Case1: for a power factor of 0.8

We would require 120kva for fulfilling the required demand. (Calculated as per equation is written above)

Case2: power factor of 1 (unity)

Here, the value of kVA required is 100 kVA. Which is less than the previous case. This indicates that the kVA demand decreases if the power factor of my equipment increases.

Ques.115. An RLC series circuit has R = 10Ω, L = 2H. What value of capacitance will make the circuit critically damped? (SSC-2015)

0.02 F

0.2 F

0.4 F

0.08 F

Answer.4. 0.08 F

Explanation:-

For critically damped RLC series circuit.

Ques.116. A primary cell has an EMF of 1.5 V. When short-circuited, it gives a current of 3 A. The internal resistance of the cell is? (SSC-2015)

0.5 ohms

0.2 ohms

2 ohms

4.5 ohms

Answer.1. 0.5 ohms

Explanation:-

When the cell is short-circuited then the current in the cell is given by

I = R/V

R = V/I

= 1.5/3 = 0.5

Ques.117. What are the maximum number of points of light, fan, and socket-outlets that can be connected in one sub-circuit? (SSC-2015)

4

12

6

10

Answer.4. 10

Explanation:-

According to Indian Electricity rules the connected load on any subcircuit consisting of tubes, fan, etc. should not exceed 800 W with a maximum of 10 points.

Ques.118. Electrical resistivity ρ is: (SSC-2015)

High for copper as well as for alloy

Low for copper and high for alloy

High for copper and low for alloy

Low for copper as well as for alloy

Answer.2. Low for copper and high for alloy

Explanation:-

Electrical resistivity, represented by ρ (rho), is a measure of how strongly a material opposes the flow of electric current. The lower the resistivity, the more readily the material permits the flow of electric charge.

The electrical resistivity of the copper is low as its conductivity is high whereas the electrical resistivity of the alloy is more.

Ques.119. A resistor is connected across a 50 V source. The current in the resistor if the color code is red, orange, orange, silver is? (SSC-2015)

21.4 mA

2 mA

2.2 mA

214 mA

Answer.3. 2.2 mA

Explanation:-

Resistor values can be known by the color band.

0 black

1 blue

2 red

3 orange

4 yellow

5 green

6 blue

7 violet

8 grey

9 white

First color = digit Second color=digit Third color= power of ten Fourth color =tolerance

In a resistor, the first color means the value first digit that is

Red – 2

Orange – 3

but that next on Orange means the power of 10

Orange – 10^{3}

that color code silver means to withstand the power of the resistor +/- 10%.

We get Resistance value from the color code (red, orange, orange, silver) is 23 (10^{3}) = 23000.

Here we are not considering the last color (tolerance-silver) Because in the question there is no specification of minimum or maximum current.