The electrical resistance of a conductor depends on its
A. Length and area of cross-section
B. Colour
C. Magnetic property
D. Transparency
Answer: Option A
Solution (By JKSSB Mock Tests)
R = ρL/A, depends on length (L), cross-sectional area (A), and resistivity (ρ) which depends on material and temperature. Not on colour or transparency.
Explanation:
An electric motor is a device that utilizes the magnetic effect of electric current. When a current-carrying coil is placed in a magnetic field, it experiences a force (Fleming's Left-Hand Rule) that causes it to rotate. Therefore, it continuously converts electrical energy into mechanical energy. A generator does the reverse.
Explanation:
Constant velocity implies zero acceleration, net force = 0 by Newton's first law. Engine force balances friction and air resistance. Net force zero, not necessarily zero forces.
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