Ohm's Law and Resistance

Q. Define Ohm's law and draw a graph for V-I.

Q. Explain the concepts of current, voltage, resistance, potential difference and ohm's law.

Q.

Which of these substances acts as a non-Ohmic

1. Nichrome wire

2. Tungsten filament

3. Copper wire

4. Aluminum filament

Q.

The law which gives a relation between electric potential difference and electric current is called ___.

1. Oersted's law

2. Faraday's law

3. Newton's law

4. Ohm's law

Q.

Please explain the working of thermocouple

Q.

What are the three forms of Ohms law?

Q. According to ohm's law, the plot of the electric current vs the potential difference in a circuit gives a straight line .

1. with constant slope
2. parallel to current axis
3. parallel to voltage axis

Q. An unknown circuit draws a current of 2 A from a 12 V battery its equivalent resistance is ________________.

1. 24 Ω
2. 6 Ω
3. 0.167 Ω
4. 10 Ω

Q. Ohm's law cannot be applied to:

1. Germanium
2. Metals
3. Silicon
4. Gases

Q. At absolute zero temperatures ..... Materials become superconductive..... Electricity pass through them without any resistance ..... According to V=IR , R becomes zero , then if resistance becomes zero do u think that any kind of potential difference exists???? And if not ...how can electrons travel through a conductor??? at such weird temperatures?

Q.

An electric circuit has a 30 V battery and a resistor of 90 ohm. Then, the current in the circuit will be:

1. 30 A

2. 0.33 A

3. 0.11 A

4. 1.30 A

Q. Question 2
Which of the following terms does not represent electrical power in a circuit?

(a) $I^{2}R$
(b) $I{R}^2$
(c) VI
(d) $\frac{V^2}{R}$

Q.

which is the best electrical conductor-copper, silver, constantan

Q. A student measures the terminal potential difference V of a cell of emf E & internal resistance r as a function of the current I flowing through it. The slope and intercept of the graph between V & I respectively equal to.? 1. E & -r 2. -r and E 3. r & -E

Q.

What are the types of LED?

Q. An increase in voltage causes an increase in _____ .

1. current
2. conductance
3. resistance
4. power

Q. Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to an electric mains supply. What current is drawn from the line if the supply voltage is 220 V?

Q. Considering the relation between current $I$, voltage $V$ and resistance $R$, which of the following equations is/are TRUE?

1. $V^2=I^2{R}^2$
2. $R^{-2}=V^{-2}{I}^2$
3. $V^2=R{I}^{-2}$
4. $V^{-2}=R^2{I}^{-2}$

Q.

If a resistance R Is melted and recast to half of its length, then the new resistance of the wire will be

1. $\frac{R}{2}$

2. $\frac{R}{4}$

3. $2R$

4. $R$

Q. An electric bell has a rating of 500 W and 100 V. It is used in a circuit having a 200 V supply. What resistance must be connected in series with the bulb so that it delivers 500 W?

1. 10 $\Omega$
2. 20 $\Omega$
3. 30 $\Omega$
4. 40 $\Omega$

Q. When the potentials of two ends of a wire differ by 10 volts, the current flowing between the two ends is recorded as 2mA. What is the resistance offered by the wire?

1. $4.5k\Omega$
2. $6k\Omega$
3. $5k\Omega$
4. $5.5k\Omega$

Q. the battery creates force to move electron called emf , and force contains by each electron is voltage and the differernce in voltage is the potential difference. Am I right ?

Q.

What is meant by an electric current? What is its unit?

Q. The equation Power $=\frac{V^2}{R}$ is valid only when the potential across the resistors are constant.

1. True
2. False

Q. In the circuit, the potential difference across $PQ$ will be nearest to :

1. $3.2V$
2. $6.6V$
3. $9.6V$
4. $4.8V$

Q.

A 10 V battery is connected to a series combination of two resistances of 4000 Ω and 6000 Ω. A non-ideal voltmeter of resistance 10, 000 Ω connected across 4000 Ω reads 3.3226 V. What would be the value
if the same voltmeter connected across 6000?

Q. A, B, and C are voltmeters of resistance $R$, $1.5R$, and $3R$ respectively. When some potential difference is applied between $X$ and $Y$, the voltmeter readings are $V_A,V_B$, and $V_C$, respectively.Then

1. $V_A=V_B=V_C$
2. $V_A\ne V_B=V_C$
3. $V_A=V_B\ne V_C$
4. $V_B\ne V_A=V_C$

Q. Ohm's law is applicable irrespective of the temperature.

1. True
2. False

Q.

which formula is used to calculate pottential difference between the ends of the conductor

Q. If a wire has resistivity $\rho$, volume $3m^3$ and resistance $3\Omega$ , then its length would be:

1. $3\times \sqrt{\frac{1}{\rho }}$
2. $\sqrt{\frac{1}{\rho }}$
3. $\frac{1}{\rho }\sqrt{3}$
4. $\rho \sqrt{\frac{1}{3}}$