class 10 electricity

class 10 electricity

Multiple Choice

When a current 'I' flows through a resistance 'R' for time 't' the electrical energy spent is given by

• (a) IRt

• (b) I²Rt

• (c) IR²t

• (d) I²R/t

Multiple Choice

Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them is in the ratio.

• (a) 2:1

• (b) 1:2

• (c) 4:1

• (d) 1:1

Multiple Choice

At a given time, a house is supplied with 100 A at 220 V. How many 75 W, 220 V light bulbs could be switched on in the house at the same time (if they are all connected in parallel)?

• (a) 93

• (b) 193

• (c) 293

• (d) 393

Multiple Choice

If the current flowing through a fixed resistor is halved, the heat produced in it will become:

• (a) One-fourth

• (b) One-half

• (c) Double

• (d) Four times