Q. If the potential difference V applied across a conductor is increased to 2V with its temperature kept constant, free electrons in a conductor will –(i) remain the same(ii) become half of its previous value(iii) be double of its initial value(iv) become zero. Answer: (iii) be double of its initial value If temperature is kept […]
Q. A constant voltage is applied between the two ends of a uniform metallic wire, heat ‘H’ is developed in it. If another wire of the same material, double the radius and twice the length as compared to original wire is used then the heat developed in it will be-(i) H/2(ii) H(iii) 2H(iv) 4H Answer:
Q. We use alloys for making standard resistors because they have(i) low temperature coefficient of resistivity and high specific resistance(ii) high temperature coefficient of resistivity and low specific resistance(iii) low temperature coefficient of resistivity and low specific resistance(iv) high temperature coefficient of resistivity and high specific resistance Answer: (i) low temperature coefficient of resistivity and
Q. By increasing the temperature, the specific resistance of a conductor and a semiconductor-(i) increases for both.(ii) decreases for both.(iii) increases for a conductor and decreases for a semiconductor.(iv) decreases for a conductor and increases for a semiconductor. Answer: (iii) increases for a conductor and decreases for a semiconductor. Specific resistance of a conductor increases
Q. An electric current is passed through a circuit containing two wires of same material, connected in parallel. If the lengths and radii of the wires are in the ratio of 3:2 and 2:3, then the ratio of the current passing through the wire will be(i) 2:3(ii) 3:2(iii) 8:27(iv) 27:8 Answer: (iii) 8:27
Q. The best instrument for accurate measurement of EMF of a cell is-(i) Potentiometer(ii) metre bridge(iii) Voltmeter(iv) ammeter and voltmeter Answer: (i) Potentiometer
The best instrument for accurate measurement of EMF of a cell is- Read More »
Q. A capacitor plates are charged by a battery with ‘V’ volts. After charging battery is disconnected and a dielectric slab with dielectric constant ‘K’ is inserted between its plates, the potential across the plates of a capacitor will become(i) Zero(ii) V/2(iii) V/K(iv) KV Answer: (iii) V/K Battery is disconnected
Q. Which statement is true for Gauss law-(i) All the charges whether inside or outside the gaussian surface contribute to the electric flux.(ii) Electric flux depends upon the geometry of the gaussian surface.(iii) Gauss theorem can be applied to non-uniform electric field.(iv) The electric field over the gaussian surface remains continuous and uniform at every
Q. Two point charges placed in a medium of dielectric constant 5 are at a distance r between them, experience an electrostatic force ‘F’. The electrostatic force between them in vacuum at the same distance r will be-(i) 5F(ii) F(iii) F/2(iv) F/5 Answer: (i) 5F
Q. Three capacitors 2μF, 3μF and 6μF are joined in series with each other. The equivalent capacitance is-(i) 1/2μF(ii) 1μF(iii) 2μF(iv) 11μF Answer: (ii) 1μF