Current Electricity

(a) Alloy used
Concept: Heating elements
Heating coils are made of materials with high resistivity and high melting point. Answer: (b) Heat produced
Concept: Joule’s Law of Heating
Step 1: Given data}
Step 2: Substitute values}
Step 3: Calculation}
Conclusion (b): (c) Effect of decreasing resistance
Step 1: Formula relation}
Step 2: Observation}
At constant voltage and time: Step 3: Conclusion}
If resistance decreases: Final Answer (c):

(A) Heating appliance
(a) Energy change
Concept:
A heating appliance converts: Conclusion (a): (b) Power calculation
Step 1: Given data}
Step 2: Formula}
Step 3: Calculation}
Conclusion (b): (B) Electric grinder
(a) Energy change
Concept:
An electric grinder converts: Conclusion (a): (b) Work done
Step 1: Given data}
Step 2: Formula}
Step 3: Calculation}
Conclusion (b):

(a) Identification of part “X”
Concept: Household wiring components
In a typical household circuit, the sequence includes: Step 1: Position of X}
The part “X” is placed after the main fuse and before ELCB. Step 2: Identify the component}
This component measures electrical energy consumed. Conclusion (a): (b) Circuit diagram of a branch circuit with three-pin socket and switch
Concept: Three-pin socket connection
A three-pin socket has:

• Live (L)
• Neutral (N)
• Earth (E)

Step 1: Connections}

• Live wire passes through a switch to the socket.
• Neutral wire directly connects to the socket.
• Earth wire connects to the earth pin.

Step 2: Diagram}
Step 3: Explanation}

• Switch is always connected in live wire for safety.
• Earth wire prevents electric shock.

Conclusion (b):

Concept: Ohmic Heating
Ohmic heating refers to the heat produced when an electric current flows through a conductor due to its resistance. This phenomenon is governed by Joule’s law. Step 1: Joule’s Law of Heating}
The heat produced in a conductor is given by: where:

• = current
• = resistance
• = time

Step 2: Meaning of Ohmic Heating}
When current passes through a resistive material, electrical energy is converted into heat energy. This is called: Step 3: Identify correct option}
Among the given options:

• Microwave → electromagnetic waves
• Induction → magnetic heating
• Radiation → heat transfer method
• Joule heating → correct definition

Conclusion: