CBSE physics
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Two wires of equal length, one of copper and the other of manganin have the same resistance. Which wire is thicker?
Resistance of a material is given by, 
Resistance for copper wire and manganin wire is given by, 
That is, manganin wire is thicker.
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What are the directions of electric and magnetic field vectors relative to each other and relative to the direction of propagation of electromagnetic waves?
Both electric and magnetic field vectors are perpendicular to each other and perpendicular to the direction of propagation.
A bar magnet is moved in the direction indicated by the arrow between two coils PQ and CD.
Predict the directions of induced current in each coil.
In the figure, N pole is receding away coil (1), so in coil (1), the nearer faces will act as S-pole and in coil (2) the nearer face will also act as S-pole to oppose the approach of magnet towards coil (2), so current in coils will flow clockwise as seen from the side of magnet. The direction of current will be from P to Q in coil (1) and from C to D in coil (2).
Mention the two characteristic properties of the material suitable for making core of a transformer.
Two characteristic properties are:
i) Low hysteresis loss
ii) Low coercivity.
A charge ‘q’ is placed at the centre of a cube of side l. What is the electric flux passing through each face of the cube?
Using Gauss theorem,
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Mock Test Series
Mock Test Series