CET/NEET - Physics

      Nature of equipotential surface for a point charge is

• Ellipsoid with charge at foci

• Sphere with charge at the centre of the sphere.

• Sphere with charge on the surface of the sphere.

• Plane with charge on the surface

A particle of mass 1gm and charge 1μC is held at rest on a frictionless horizontal surface at distance 1m from fixed charge 2mC. If the particle is released, it will be repelled. The speed of the particle when it is at a distance of 10m from the fixed charge.

• 60 ms^-1

• 100 ms^-1

• 90ms^-1

• 180ms^-1

Four metal plates are arranged as shown. Capacitance between X and Y (A = Area of each plate, d = distance between the plates).

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Two point charges A = +3nC and B = +1nC are placed 5 Cm apart in air. The work done to move charge B towards A by 1 Cm is

• 1.35 X 10^{- 7}J

• 2.7X 10^{- 7}J

• 2X 10^{- 7}J

• 12.1X 10^{- 7}J

A system of two capacitors of capacitance 2μF and 4μF is connected in series across a potential difference of 6V. The electric charge and energy stored in the system are

• 10μC and 30μ J

• 36μC and 108μ J

• 8μC and 24μ J

• 1μC and 3μ J

The minimum value of effective capacitance that can be obtained by combining 3 capacitors of capacitances 1pF, 2pF and 4pF is

• 0.57pF

• 1pF

• 1.75pF

• 2pF

For the arrangement of capacitors as shown in the circuit, the effective capacitance between points A and B is

• 4μF

• 2μF

• 1μF

• 8μF

The work done to move a charge on any equipotential surface is

• Infinity

• Less than 1

• Greater than 1

• Zero

Two capacitors of 3μF and 6μF are connected in series and a potential difference of 900V is applied across the combination. They are then disconnected and reconnected in parallel. The potential difference across the combination is

• Zero

• 100V

• 200V

• 400V

Two metal plates are separated by 2 Cm. The potentials of the plates are – 10 V and + 30V. The electric field between the two plates is

• 500V/m

• 1000V/m

• 2000V/m

• 3000V/m