(A) (i) List any two features of the electric current used in the houses of India.

(ii) Write any two differences between direct current and alternating current.

(iii) How will you identify the live wire and the neutral wire in a domestic electric circuit?

OR

(B) (i) Why is fuse an important component in our electric circuits?

(ii) Distinguish between overloading and short-circuiting of a circuit.

(iii) Giving reason, explain what type of materials are used in fuse wires.

Note on grounding: Only the fuse mechanism and Joule heating below are drawn directly from Section 11.7 of this NCERT chapter ("Electricity"), which discusses Joule's law of heating and the fuse. The chapter, as given in this book, does NOT contain a separate section on domestic wiring, live/neutral/earth wires, line testers, AC/DC waveform comparison, or the terms "overloading"/"short-circuiting"; those parts of the answer are standard, factually correct general knowledge (also covered elsewhere in the CBSE Class X curriculum) and are presented here as supplementary context, not as chapter citations.

(A)(i) Features of Indian domestic supply: The electric mains supply used in Indian homes has a potential difference of 220 V and is alternating current (AC) with a frequency of 50 Hz. (This specific fact is general knowledge/curriculum content; it is not stated verbatim in this chapter, which works mostly with DC cells/batteries in its examples.)

(A)(ii) DC vs AC:

(A)(iii) Identifying live and neutral wires: In a domestic circuit there are three wires — live (usually red/brown insulation), neutral (black/blue insulation), and earth. The live wire carries the alternating potential and is at a high potential (about 220 V) with respect to the earth/neutral, while the neutral wire is nominally at zero (earth) potential. To identify them practically, a line tester (a screwdriver containing a neon bulb connected between its tip and a metal contact on the cap, with a high resistance in between) is touched to each wire while the user's finger touches the metal cap: the neon bulb glows when the tester touches the live wire (current flows to earth through the body's high resistance, lighting the neon lamp) and does not glow for the neutral wire.

OR (B)(i) Importance of a fuse: Section 11.7 of the chapter explains that the generation of heat in a conductor (Joule heating, $H=I^2Rt$) is an unavoidable consequence of current flow, and that a fuse — a wire of a metal/alloy of appropriate melting point placed in series with the circuit — protects the circuit and appliances by melting and breaking the circuit if a current larger than the specified/rated value flows through it. (The specific terms "overloading" and "short-circuiting" as causes of excess current are general-knowledge elaborations, not phrases used in this chapter, but they correctly describe real situations that make the current exceed the fuse's rated value.)

(B)(ii) Overloading vs Short-circuiting:

• Overloading: Occurs when too many appliances are connected to and drawing current from a single circuit/socket simultaneously (or the demand due to load is too high), so that the total current exceeds the safe carrying capacity of the wires, causing excessive heating.
• Short-circuiting: Occurs when the live wire and the neutral wire come into direct contact (e.g., due to damaged/worn-out insulation), which suddenly reduces the resistance of the circuit to nearly zero. By Ohm's law $I=V/R$, this causes an abnormally and suddenly high current to flow, producing intense heat almost instantaneously.

(B)(iii) Material for fuse wires: As stated in Section 11.7, "[the fuse] consists of a piece of wire made of a metal or an alloy of appropriate melting point, for example aluminium, copper, iron, lead etc." Such wires (a) have an appropriately low melting point, so that they melt and break the circuit quickly once the current exceeds the rated safe value, and (b) have suitable resistance so that under normal safe currents they do not heat up enough to melt, only doing so under a fault (overload/short-circuit) condition. The chapter's own worked example illustrates this: for a 1 kW, 220 V electric iron drawing (1000/220) A = 4.54 A, a 5 A rated fuse must be used, showing how the fuse wire's melting/rated current is matched to the appliance's normal operating current.