Electricity — Important Questions

The same current flows through each resistor

Step 1: In a series circuit, there is only one path for current to flow. Step 2: Since all components are in a single loop, the same current passes through each resistor. Step 3: The total voltage is divided across the resistors (not the same across each). Step 4: The equivalent resistance is greater than the highest individual resistance. In a series circuit, if one component fails, the entire circuit breaks — unlike parallel circuits.

18 Ω

Step 1: For resistors in series, the equivalent resistance is Rs = R1 + R2 + R3. Step 2: Substitute the values: Rs = 6 + 6 + 6. Step 3: Rs = 18 Ω. Option 2 Ω is the answer if they were in parallel (R/n = 6/3 = 2). Option 6 Ω is just one resistor's value. Option 36 Ω results from multiplying (6 × 6 = 36, which is wrong).

Potential difference across each resistor

Step 1: In a parallel circuit, all resistors are connected between the same two points (A and B). Step 2: Since they share the same two end points, the voltage (potential difference) across each resistor is equal. Step 3: However, the current through each resistor is different (I = V/R), with smaller resistors carrying more current. This is why all appliances in a house get 220 V — they are all connected in parallel.

Heating effect of current

Step 1: When current flows through a conductor, the moving electrons collide with atoms of the conductor. Step 2: These collisions transfer energy to the atoms, causing them to vibrate faster, which produces heat. Step 3: This is called the heating effect of current and is described by Joule's Law (H = I²Rt). This effect is used in electric irons, heaters, and toasters. The other options — magnetic effect, chemical effect, and photoelectric effect — are different phenomena.