CRT 2 (CBSE 10th)

The heating element of an electric iron is made up of:

• copper

• nichrome

• aluminium

• iron

Electrical resistivity of any given metallic wire depends upon

• its thickness

• its shape

• nature of the material

• its length

Electric power is inversely proportional to

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 (i)

• Maximum in case (ii)

• Maximum in case (iii)

A current of 0.5 A is drawn by a filament of an electric bulb. Number of electron passing through a cross-section of the filament in 32 seconds would be roughly

• 10¹⁸

• 10¹⁶

• 10²⁰

• 10²³

What is the minimum resistance which can be made using five resistors each of 1/2 Ω?

• 1/5

• 1/25

• 1/10

• 25

The proper representation of series combination of cells obtaining maximum potential is

• i

• ii

• iii

• iv

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 as shown in figure. Which of the following is true?

• R₁ = R₂ = R3

• R₁ > R₂ > R₃

• R₃ > R₂ > R₁

• R₂ > R₃ > R₁

In an electrical circuit, two resistors of 1/2 $\Omega$   and 1/4 $\Omega$   respectively are connected in series to a 6V battery. The heat dissipated by the 1/4  $\Omega$   resistor in 5s will be

• 20J

• 40J

• 80J

• 160J

If the potential difference across the ends of a conductor is doubled, the current flowing through it, gets ………