ICSE physics
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Question
Write Coulomb’s Law in vector form.
Solution
Coulomb's law in vector form is expressed as:
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Question
How much kinetic energy is gained by an electron, initially at rest, when it moves through a potential difference of 1000 V ? Leave your answer in Joule.
Solution
Given,
V = 1000 V
K.E. = eV
= 1.6 x 10-19 x 1000
K.E. = 1.6 x 10-16 J, kinetic energy
Question
A wire of resistivity y is stretched uniformly so that its length becomes four times. What is its new resistivity ? (Assume temperature of the wire remains constant during stretching of the wire.)
Solution
Resistivity does not depend on the dimensions of wire so it will remain the same.
Question
Show graphically how electrical resistance of a piece of Silicon or Germanium varies when its temperature is varied.
Solution
Graph between resistances and temperature of Silicon or Germanium is as given below:
Question
A circular coil having 50 turns, each with an area of 0.01 m2, carries a current of 2A. Calculate its magnetic dipole moment.
Solution
Magnetic moment associated with the coil is,
m = N.I.A
Here, N = 50
I = 2 A
A = 0.01 m2
∴ m = 50 x 2 x 0.01
= 1 Am2
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Mock Test Series
Mock Test Series