Advertisements
Advertisements
प्रश्न
Fig. shows a 3 pin plug with the cover removed. The electric cable
connected to the plug contains 3 wires with colour coded insulation namely brown, blue and green.
- Identify each of the colour coded wires by stating to which of the
terminals A, B or C in the diagram they should be connected. - Identify the terminal through which no current passes in normal
circumstances. - What is the purpose of the earthed wire connected to an electric
appliance like an electric heater? Describe how it works.
Advertisements
उत्तर
(a) Brown wire or live wire should be connected to terminal C.
Blue wire or neutral wire should be connected to terminal B.
Green wire or earth wire should be connected to terminal A.
(b) No, current passes through the earth terminal i.e. terminal A in normal circumstances.
(c) The metal case of an electrical appliance is earthed so that in any case of accidental contact of live wire with the metallic body of the appliance, the earth wire would provide a safe and easy path for the electric charges to flow down to the earth which acts as very large sink. Thus, user is thereby protected from any fatal electric shock.
APPEARS IN
संबंधित प्रश्न
In which direction do electrons flow?
Consider the circuit given below:
(a) In which circuit are the lamps dimmest?
(b) In which circuit or circuits are the lamps of equal brightness to the lamps in circuit (i)?
(c) Which circuit gives out the maximum light?
The rating of a fuse connected in the lighting circuit is:
(a) 15 A (b) 5 A (c) 10 A (d) Zero
A wire of length 5 m has a resistance of 2.0 Ω calculate:
(a) the resistance of wire of length 1 m
(b) the equivalent resistance if two such wires each of length 2 m are joined in parallel.
(c) the resistance of 1 m length of wire of same material but of half diameter.
In a house there are 6 bulbs of 100 W each used for 4 hours a day, 4 bulbs of 60 W each used for 8 hours a day, an immersion heater of 2.5 kW used for 1 hour per day, and an electric iron of 800 W used for 2 hours per day. Calculate the cost of monthly electric bill for the month of April at the rate of 80 p per unit.
An electric oven is rated as 1.5 kW, 250 V. If it is connected to a 250 V mains, calculate the
(a) Current drawn,
(b) Energy consumed in 20 hours,
(c) Cost of energy consumed in 20 hours at the rate of Re. 1 per unit.
Tick (✓) the correct choice among the following :
There are 500 turns and 2000 turns in the primary and secondary coil of a
transformer respectively. If th e output voltage is 1000 V, how large is the
input voltage?
Which part of an electrical appliance is earthed?
State whether true or false. If false, correct the statement.
Current can produce magnetic field.
Match the items in column-I to the items in column-II:
| Column - I | Column - II |
| (i) electric current | (a) volt |
| (ii) potential difference | (b) ohm meter |
| (iii) specific resistance | (c) watt |
| (iv) Electrical power | (d) joule |
| (v) electrical energy | (e) ampere |
