Advertisements
Advertisements
Question
The resistance of a nichrome wire at 0°C is 10Ω. If its temperature coefficient of resistivity of nichrome is 0.004/ °C, find its resistance of the wire at boiling point of water. Comment on the result.
Advertisements
Solution
Given data:
R0 = 10Ω
The boiling point of water T = 100°C
α = 0.004°C
RT = ?
Formula:
RT = R0 [l + αT)]
RT = 10 [1 + (0.004 × 100)]
= 10(1 + 0.4)
= 10 (1.4)
RT = 14Ω
As the temperature increase the resistance of the wire also increases.
APPEARS IN
RELATED QUESTIONS
Ohm's law gives a relationship between:
(a) current and resistance
(b) resistance and potential difference
(c) potential difference and electric charge
(d) current and potential difference
How should the two resistances of 2 ohms each be connected so as to produce an equivalent resistance of 1 ohm?
An electric bulb draws 1.2 A current at 6.0 V. Find the resistance of filament of bulb while glowing.
A wire of resistance 9 ohm having length 30 cm is tripled on itself. What is its new resistance?
Show by a diagram how two resistors R1 and R2 are joined in parallel. Obtain an expression for the total resistance of the combination.
In the circuit shown below in Fig, calculate the value of x if the equivalent resistance between A and B is 4 Ω.
The filament of a bulb takes a current 100 mA when potential difference across it is 0.2 V. When the potential difference across it becomes 1.0 V, the current becomes 400 mA. Calculate the resistance of filament in each case and account for the difference.
The temperature of a conductor is increased. The graph best showing the variation of its resistance is:
Assertion: The statement of Ohm’s law is K = IR.
Reason: V = IR is the equation which defines resistance.
Two cells of same emf E but internal resistance r1 and r2 are connected in series to an external resistor R (Figure). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.
