Advertisements
Advertisements
प्रश्न
How does the resistance of a wire change when:
its length is tripled?
उत्तर
Resistance,
`R=l/A`
where l = length of wire
A= area of cross-section of the wire
When the length is tripled, l' = 3l
New resistance,
`R'=l/A `
`R'=(rho(3l))/A=(3l)/A`
`R=3R`
`R=P/A`
Thus, the resistance will become three times the original resistance.
APPEARS IN
संबंधित प्रश्न
In series combination which remains constant?
(a) Voltage
(b) Current
(c) Both current and voltage
(d) Both are variables
Complete the following :-
(a)
The substance having infinitely high electrical resistance is called:
(a) conductor
(b) resistor
(c) superconductor
(d) insulator
How does the presence of impurities in a metal affect its resistance?
Choose the correct alternative and rewrite the following:
You are given three equal resistances. In how many combinations can they are arranged?
Answer the following question.
While studying the dependence of potential difference ( V) across a resistor on the current (I) passing through it, in order to determine the resistance of the resistor, a student took 5 readings for different values of current and plotted a graph between V and t. He got a straight line graph passing through the origin. What does the straight-line signify? Write the method of determining the resistance of the resister using this graph.
A given metallic wire of resistance R is doubled on itself. What will be its new resistance?
Write an expression for the resistance of a conducting wire in terms of its length and area of cross-section.
What should be the length of a nickel wire of area of cross-section 3 mm2 used for making a rheostat of 750 ohm? (ρ of nickle = 0.069 Ohm mm2/m)
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:
