Explore topic-wise InterviewSolutions in Current Affairs.

Correct option is: C) potential difference between A and B

No, they don’t move. They are fixed in the lattice. Eg : battery.

C) either A or B

No, they lose energy and are again accelerated by the electric field.

C) Both A and B

Correct option is  B) 5 A

Correct option is  B) Loop law

R, R, R Ω resistances are in parallel. ⇒ Resultant resistance = R/3

Potential difference (P.D) = work done/charge = W/Q

n = 10; R = 20 Ω 

In series connection resultant resistance 

R’ = nR = 10 × 20 = 200 Ω

In parallel connection resultant resistance R' = R/n = 20/10 = 2Ω

Correct option is: (D) unchanged

Correct option is  D) halved

Correct option is   A) four times

Correct option is  D) All

A) Both X and Y are correct

Correct option is: A) both a and b are correct

D) The fuse wire consists of a thick wire of high melting point.

Negative type of charge flows through an electric wire when it is connected in an electric circuit.

A) Kirchhoff’s Junction law

Correct option is  B) 7 V

Correct option is: (D) high potential.

Correct option is  D) insulator

Correct option is  B) half

1) The electric wiring for light and fan circuit uses a thin fuse wire of low current carrying capacity because the line wire has a current carrying capacity of 5A.

2) Thicker fuse wires of higher current carry ing capacity (15 A) are used for large current consuming appliances such as air conditioner, geyser, washing machine, etc. because the line wire for such dev ices have current carrying capacity of 15A. 

The current rating of a fuse in a circuit can be obtained by the following relation.

Current rating of fuse = Total power of appliances in that circuit/ Voltage of the supply

1. These days instead of fuses, Miniature Circuit Breakers (MCB) are used for each lighting circuit. 

2. They switch off the circuit in a very short time duration in case of short-circuiting or some fault in the line. 

3. After repairing the fault in the circuit, the MCB is again switched on. 

4. Thus, the use of MCB is better than a fuse. It avoids the inconvenience of connecting a new fuse wire and it is much safer due to its quick response.

Correct option is  B) negative

Both are different because potential difference is the work done by the electric force on unit positive charge to move it through a distance between two points whereas emf is the chemical force to move unit positive charge from negative terminal to positive terminal of the battery.

The materials whose resistivity is 10⁵ to 10¹⁰ times more than that of metals and 10¹⁵ to 10¹⁶ times less than that of insulators. 

Eg: Silicon, Germanium,

1. Resistivity (ρ) is a property of a material, while the resistance (R) refers to a particular object.

2. The electric field \(\overrightarrow{E}\) at a point is specified in a material with the potential difference across the resistance and the current density \(\overrightarrow{J}\) in a material is specified instead of current I in the resistor.

3. For an isotropic material, resistivity is given by ρ = \(\frac{E}{J}\)

For a particular resistor, the resistance R given by, R = \(\frac{V}{I}\)

Diode and electrolytes.

Correct option is  D) ohm

B) Resistance of a conductor is directly proportional to its length

Resistivity of a conductor depends upon temperature as
ρ = ρ₀(l + α Δt)

C) insulators

A) Both statements are true

(A) length of the conductor.

Correct option is: (C) \(\frac{v_d}{2}\)

i. The valence electrons become de-localized when a large number of atoms come together in a metal. 

ii. These electrons become conduction electrons or free electrons constituting an electric current when a potential difference is applied across the conductor.

D) Both B and C

E = 24 V, r = 380 Ω

i. Maximum current (I_max)

ii. Can battery start the motor?

Formula : I_max = E/r

Calculation : From formula,

I_max = 24/380 = 0,063 A

As, the value of current is very small compared to required current to run a starting motor of a car, this battery cannot be used to drive the motor.

Correct option is: (D) 3 Ω

Given: E = 12 volt, r = 10 Ω, R = 230 Ω

To find: Reading shown by voltmeter (V)

Formula: i. I = \(\frac{E}{R+r}\)

ii. V = E – Ir

Calculation:

From formula (i),

I = \(\frac{12}{230+10}=\frac{12}{240}=\frac{1}{20}\) A

From formula (ii),

V= 12 – \(\frac{1}{20}\) × 10 = 12 – 0.5

= 11.5 volt

Given: E = 10 V, r = 3 Ω, I = 0.5 A

To find: i. Resistance of resistor (R)

ii. Terminal voltage of battery (V)

Formula: I = \(\frac{E}{R+r}\)

Calculation: From formula, R = \(\frac{E}{I}-r\)

∴ R = \(\frac{10}{0.5}-3\) = 17 Ω

∴ V = IR = 0.5 × 17 = 8.5 volt

Electric current is defined as the amount of charge crossing any cross-section of the conductor in one second.

C) there is no potential difference between the legs of a bird

When the bird stands on a high voltage wire, there is no potential differences between the legs of the bird, so no current passes through the bird.

1. There are two parallel lines carrying 240 V current. The voltage current will pass through the body if both the wires are touched at the same time. But, when the bird stands on only one wire, there is no potential difference between the legs. 

2. So, no current passes through the bird. Hence, it doesn’t feel any electric shock.

Correct option is: C) on potential difference and resistance

This is due to forward voltage and maximum continuous current rating characters of LEDs.

Correct option is C) 4 Ω