Joule's Law of Heating

Q. Question 4
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be –

(a) 1:2
(b) 2:1
(c) 1:4
(d) 4:1

Q.

What is the effect of an increase in temperature on resistance?

Q. Question 15
In an electrical circuit two resistors of 2 $\Omega$ and 4 $\Omega$ respectively are connected in series to a 6 V battery. The heat dissipated by the 4 $\Omega$ resistor in 5 s will be

(a) 5 J
(b) 10 J
(c) 20 J
(d) 30 J

Q.

Question 2
In the following circuits (figure), heat produced in the resistor or combination of resistors connected to a 12V battery will be


(a) same in all the cases
(b) minimum in case (i)
(c) maximum in case (ii)
(d) maximum in case (iii)

Q.

Why we cannot use a bulb instead of a resistor in ohm law

Q. Question 9
A battery of 9 V is connected in series with resistors of $0.2\Omega ,0.3\Omega ,0.4\Omega ,0.5\Omega$ and $12\Omega$, respectively. How much current would flow through the $12\Omega$ resistors?

Q. Question 15
In an electrical circuit two resistors of 2 $\Omega$ and 4 $\Omega$ respectively are connected in series to a 6 V battery. The heat dissipated by the 4 $\Omega$ resistor in 5 s will be

(a) 5 J
(b) 10 J
(c) 20 J
(d) 30 J

Q.

What is a Bunsen burner used for?

Q. Question 15
In an electrical circuit two resistors of 2 $\Omega$ and 4 $\Omega$ respectively are connected in series to a 6 V battery. The heat dissipated by the 4 $\Omega$ resistor in 5 s will be

(a) 5 J
(b) 10 J
(c) 20 J
(d) 30 J

Q. List down the properties of a high tension wire.

Q. Match the following with the correct pair.

1. Safety device
2. $Charge/Time$
3. Heating effect

Q. Calculate the heat dissipated across $6\Omega$ and $4\Omega$ resistors in 30 seconds.

1. $30\text{J},45\text{J}$
2. $45\text{J},30\text{J}$
3. $125\text{J},187.5\text{J}$
4. $187.5\text{J},125\text{J}$

Q. A $6V$ battery is connected across a lamp whose resistance is $20\Omega$. Calculate the value of the extra resistance which must be used in the circuit to get $0.25A$ current in the circuit.

1. $4\Omega$
2. $6\Omega$
3. $2\Omega$
4. $8\Omega$

Q.

Cryogenics is used for power transmission in big cities. Justify this statement.

Q. A $6V$ battery is connected across a lamp whose resistance is $20\Omega$. Calculate the value of the extra resistance which must be used in the circuit to get $0.25A$ current in the circuit.

1. $4\Omega$
2. $6\Omega$
3. $2\Omega$
4. $8\Omega$

Q. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be:

1. 1:4
2. 4:1
3. 2:1
4. 1:2

Q. If I were to use measure changing temperature using a resistor, how would I do it?

1. Pass a current through the resistor and measure it. Change in current will give change in temperature.
2. Connect a battery across the resistor. The battery's supply voltage changes with temperature.
3. The resistor will change shape noticably for even small changes in temperature.
4. I'll just use a thermometer

Q. Question 2
In the following circuits (Figure), heat produced in the resistor or combination of resistors connected to a 12V battery will be


(a) same in all the cases
(b) minimum in case (i)
(c) maximum in case (ii)
(d) maximum in case (iii)

Q. In a bulb, electrical energy is converted into .

1. potential energy
2. kinetic energy
3. light energy

Q. According to Joules law, if the potential difference across a conductor of resistivity $\rho$ remains constant, then the heat produced is proportional to:

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

Q.

The magnetic effect of current was first discovered in:

1. 1877

2. 1890

3. 1855

4. 1820

Q. Tungsten is not an ideal material for making fuse.

1. False
2. True

Q. When a bulb glows it emits both heat and light.

1. False
2. True

Q. If I were to use measure changing temperature using a resistor, how would I do it?

1. I'll just use a thermometer
2. Pass a current through the resistor and measure it. Change in current will give change in temperature.
3. Connect a battery across the resistor. The battery's supply voltage changes with temperature.
4. The resistor will change shape noticably for even small changes in temperature.

Q. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be:

1. 1:4
2. 4:1
3. 1:2
4. 2:1

Q. Nichrome and copper wires of same length and same radius are connected in series. Current I is passed through them.Which wire gets heated up more ? Justify your answer.

Q. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be:

1. 4:1
2. 2:1
3. 1:2
4. 1:4

Q. Which of the following effects of electric current is made use of in the figure shown below?

1. Heating
2. Magnetic
3. Chemical
4. All of the above.

Q. Observe the circuit diagram given below and answer the following questions.
a. Which are the instruments labeled as P and Q in the diagram?
b. If you replace the copper wire AB with a Nichrome wire of same length and area of cross-section.
i. What change would you notice in the reading on the device Q? Why?
ii. What will happen to the heat produced in the conductor? Explain with reference to Joule's Law.

Q. Which of the following devices work on the heating effect of electric current?

1. Fan
2. Radio
3. Geyser
4. Phone
5. Bulb
6. Oven
7. Switch
8. Electric iron
9. Cell
10. Toaster