Resistance

Q. please provide numerical problems from chapter electricity for practice.

Q.

What are the factors affecting resistance?

Q.

What are ohmic and non-ohmic devices? Give examples.

Q.

Why is AC used for long distance power transmission instead of DC?

1. AC has lower risk of shock than DC

2. AC dissipates lower power than DC in a current carrying wire

3. It is more convenient to step up/down voltage for AC than DC

4. Power dissipation in AC is lower since frequency is high

Q.

Why electric field is normal to surface of conductor?

Q.

1 ohm is equal to_________.

Q. With increase in temperature, the resistivity of a semiconductor _________ .

1. increases
2. decreases
3. becomes zero
4. remains constant

Q. Two straight parallel conductors carrying current in the same direction are placed close to each other. How will they react?

Q.

1 mega ohm = _____________.

1. 10³ ohm

2. 10 ohm

3. 10⁵ ohm

4. 10⁶ ohm

Q.

Define one ohm

Q.

A wire of resistance 20 ohm is bent in form of a circle. Find the equivalent resistance between two diametrically opposite ends.

1. 10 ohm

2. 5 ohm

3. 40 ohm

4. 20 ohm

Q.

Question 11
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances $R_1$, $R_2$ and $R_3$ respectively (figure). Which of the following is true?


(a) $R_1=R_2=R_3$
(b) $R_1>R_2>R_3$
(c) $R_3>R_2>R_1$
(d) $R_2>R_3>R_1$

Q. All formula for the physics chapter electricty.

Q.

Three resistances 12 ohms each are connected in parallel. Three such combinations are connected in series. What is the total resistance in ohms?

1. 12 ohms

2. 20 ohms

3. 24 ohms

4. 16 ohms

Q. What is double staircase wiring?

Q.

Define the term resistance. State its S.I. Unit.

Q.

Two wires A and B of same matel have the same area of cross section and have their lengths in the ratio 2:1. What will be the ratio of currents flowing through them, when the same pottential difference is applied across length of each of them ....??

Q.

How does the resistance of a wire depend on its radius?

Q.

How is potential difference measured?

Q.

What happens when the ammeter is connected in parallel and the voltmeter is connected in series?

Q. The wattage of a bulb is 24W when it is connected to a 12 v battery. Calculate the effective wattage if it operates on 6v battery. Calculate the wattage if it operates on a 6 v battery.
Which of the following solution is correct for the above question and why and how to know which way to do?

Solution 1:-
P=V*I
I=P/V
I=24/12
I=2 A
Now V = 6v
New P = V*I = 6*2 = 12W

Solution 2:-
P = V^{​​​​​​2}/R
R = V^{​​​​​​2}/P
R = 12²/24
R = 6 Ohm

Q. A given length of a wire is doubled on itself and this process is repeated once again then by what factor does the resistance of the wire change?

Q.

Identify the circuit in which the electrical components have been properly connected.

1. 

2. 

3. 

4. 

Q.

How do you create a potential difference?

Q.

Is resistance constant in Ohms law?

Q. Two resistors, with resistance 10 Ohm and 15 Ohm are connected to a battery of emf (voltage) 12 volt so as to obtain (a) minimum current (b) maximum current (i) Describe the mode of connecting the resistance in each case. (ii) Calcualte the strength of total current in the circuit in each case (ii) Also find total resistance

Q.

In a series electrical cicuit comprising a resistor made up of metallic wire, the ammeter reads 100mA. If the length of the wire is doubled, how will the current in the circuit change? Justify your answer.

Q.

Name the physical quantity whose unit is " ohm".

Q.

What happens to the resistance of a circuit if the current through it is doubled

Q.

The resistance of a conductor does not depend upon?

1. The length of the conductor.

2. The humidity of the conductor

3. The thickness Of the conductor.

4. The temperature of the conductor.