Electricity 1

In the following circuits heat produced in the resistor or combination of resistors connected to a 12 V battery will be

• same in all the cases

• maximum in case (ii)

• minimum in case (i)

• maximum in case (iii)

Electrical resistivity of a given metallic wire depends upon

• its length

• its shape

• its thickness

• nature of the material

Which of the following represents voltage?

• Work done / Current x Time

• Work done × Charge

• Work done × Time / Current

• Work done × Charge × Time

A cylindrical conductor of length l and uniform area of crosssection A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross section

• A/2

• 3A/2

• 2A

• 3A

A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1 , R2 and R3 respectively (Figure.12.5). Which of the following is true?

• R1 = R2 = R3

• R1 > R2 > R3

• R3 > R2 > R1

• R3 > R1 > R2

What is the maximum resistance which can be made using five resistors each of 1 Ω?

• 1/5

• 10

• 1

• 5

The resistivity does not change if the material is changed

• the material is changed

• the temperature is changed

• the shape of the resistor is changed

• both material and temperature are changed

What is the minimum resistance which can be made using five resistors each of 1 ohm?

• 1/5 ohm

• 1/25 ohm

• 1/10 ohm

• 25 ohm

In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be

• 5 J

• 10 J

• 20 J

• 30 J

An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?

• 1 A

• 2 A

• 4 A

• 5 A