Advertisements
Advertisements
प्रश्न
Define the term resistivity and state its S.I. unit. Which will have higher resistivity a conductor or an insulator.
Advertisements
उत्तर
The resistivity of a substance is the resistance of a wire of that substance of unit length and unit area of cross-section. Its S. I. unit is ohm × m. An insulator will have higher resistivity.
APPEARS IN
संबंधित प्रश्न
A battery of 9 V is connected in series with resistors of 0.2 Ω, 0.3 Ω, 0.4 Ω, 0.5 Ω and 12 Ω, respectively. How much current would flow through the 12 Ω resistor?
Two resistors of 4Ω and 6 Ω are connected in parallel to a cell to draw 0.5 A current from the cell.
(i) Draw a labelled circuit diagram showing the above arrangement.
(ii) Calculate the current in each resistor. What is an Ohmic resistor?
Write down an expression for the resistance of a metallic wire in terms of the resistivity.
How does the resistance of a wire change when:
its length is tripled?
Name the material of wire used for making standard resistances. Give a reason.
The voltage applied to a given rheostat is made four times its initial value. By what factor will be resistance of the rheostat change?
Illustrate-combination of cells e.g., three cells, in parallel, explaining the combination briefly. Obtain an expression for current ‘i’ in the combination.
Calculate the value of the resistance which must be connected to a 15 ohm resistance to provide on effective resistance of 6 ohm.
If R1 and R2 be the resistance of the filament of 40 W and 60 W respectively operating 220 V, then:
