ELECTRICITY AND CIRCUITS

In an electric bulb, light is produced due to the glowing of

• the glass case of the bulb

• the thin filament

• the thick wires supporting the filament

• gases inside glass case of the bulb.

In the circuit shown in figure, when the switch is moved to ’ON’ position...…then

• the bulb A will glow first

• the bulb B will glow first

• the bulb C will glow first

• all bulbs will glow together.

Bob connected two bulbs to a cell as shown f in figure, She found that filament of bulb B is broken. Will the bulb A glow in this circuit? Give reason.

• NO

• YES

• No, the bulb will not glow in this circuit as the filament of bulb B is broken. So the circuit remains incomplete.

• Yes, the bulb will glow as the filament of A is not broken

Figure shows a bulb with its different parts marked as 1,2,3,4 and 5. Which of them label the terminals of the bulb?

• 5 and 4

• 3 and 4

• 2 and 4

• 1 an 4

Figure A and B, show a bulb connected to a cell in two different ways.

(i) What will be the direction of the current through the bulb in both the cases (Q to P orPto Q)?

(ii) Will the bulb glow in both the cases?

(iii) Does the brightness of the glowing bulb depend on the direction of current through it?

• (i) In case of A: P to Q

  In case of B: Q to P

  (ii) Yes the bulb will glow in both the cases as the circuit is complete in both the cases.

  (iii) No, the brightness of the glowing bulb does not depend on the direction of current through it.

• (i) In case of A: Q to P

  In case of B: P to Q

  (ii) No, because the current flowing in A is not from positive to negative

  (iii) No, the brightness of the glowing bulb does not depend on the direction of current through it.

• (i) In case of A: Q to P

  In case of : P to Q

  (ii) Yes, the bulb will glow in both the cases as the circuit is complete in both the cases.

  (iii) No, the brightness of the glowing bulb does not depend on the direction of current through it.

To prevent electric shocks, the metallic electrical wires are covered with

• paper

• cotton

• plastic

• aluminum