Advertisements
Advertisements
प्रश्न
How does the resistance of a wire change when:
its length is tripled?
Advertisements
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
Find the expression for the resistors connected in series and write the two characteristics of it. (Draw figure).
How does the resistance of a pure metal change if its temperature decreases?
A p.d. of 4 V is applied to two resistors of 6 Ω and 2 Ω connected in series. Calculate:
(a) the combined resistance
(b) the current flowing
(c) the p.d. across the 6 Ω resistor
What is the equivalent resistance between A and B in the given circuit (Fig?)
What do you mean by power rating of an electrical appliance? How do you use it to calculate
(a) the resistance of the appliance and
(b) the safe limit of the current in it, while in use?
To increase the effective resistance in a circuit, the resistors are connected in _______________ .
Name the material of wire used for making standard resistances. Give a reason.
How does the resistivity of an alloy such as constantace depends on temperature.
State expression for Resistance connected in parallel.
State expression for Cells connected in parallel.
Calculate the equivalent resistance between the points A and B for the following combination of resistors:
A metal wire of resistance 6 Ω is stretched so that its length is increased to twice its original length. Calculate its new resistance.
If R1 and R2 be the resistance of the filament of 40 W and 60 W respectively operating 220 V, then:
If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be:
When a 4 Ω resistor is connected across the terminals of a 2 V battery, the number of coulombs passing through the resistor per second is:
