(ii) explain the reason for the difference in resistance.
(ii) Resistance of the filament of the bulb increases with increase in temperature. Hence when it glows its resistances is greater than when it is cold.
Question: Calculate the resistance of 1 km long 1 0-8 of radius 1 mm. (Resistivity of copper = 1.72 x
R = 1 mm = 1 x 1 0-3
Question: When a potential difference of 2 V is applied across the ends of a wire of 5 m length, a current of 1A is found to flow through it. Calculate: (i) the resistance per unit length of the wire (ii) the resistance of 2 m length of this wire (iii) the resistance across the ends of the wire if it is doubled on itself.
Answer: (i) V = I R ----- Ohm's law R=V/I=2/1= 2 Ohm
Resistance per unit length: 2/5= 0.4Ohm/m
(ii) Resistance of 2 m length of the wire = 0.4 x 2=0.8 ohm
(iii) When the wire is doubled on itself:
(1) the area of cross-section is doubled. If A is the original C.S. area, now it is 2 A.
(2) The length becomes half i.e.L/2
Resistance of this wire =R' = p (l/2)/(2A) = 1/4(p(L/A)
But p(L/A) = 2 ohm
Guess Paper SA-1- 2011 - X -Science-Electricity and its effects
10th science physics Electric current and its effects notes
10th science physics Electric current and its effects Solved questions (1-2 marks)
10th science physics Electric current and its effects Test Paper
NUMERICAL - Electricity & its effects For (Class X unsolved)
Solved Electricity numerical for class 10
Current Electricity Numerical solved
MCQ physics 10th Chapter Electric current and its effects
Electric current and its effects: An Introduction To Electrical Power And Energy
Electric current and its effects: An Introduction To Electric Potential and Potential Difference
QUESTION BANK Class X Physics (Electricity)
CBSE PHYSICS : 10th Electric Current & and Its Effect Multiple choice questions
ELECTRIC CURRENT AND CIRCUIT+ Revision Notes