Physics-DPP-7-Electrostatics

PHYSICS Topic: ELECTROSTATICS Date: 1. The equivalent capacity across M and N in the given figure is : (a) 5C / 3 (b) 2 / 3 C (c) C (d) 3 / 2 C 2. A parallel plate condenser with air between the plates possesses the capacity of 10–12 F. Now the plates are removed apart, so that the separation is twice the original value. The space between the plates is filled with a material of dielectric constant 4.0. Then new value of the capacity is (in farad) : (a) 4 ´ 10–12 (b) 3 ´ 10–12 (c) 2 ´ 10–12 (d) 0.5 ´ 10–12 3. Calculate the Capacitance between point A & B. : (a) 2 C (b) 4 C (c) C/4 (d) C 4. Consider a system composed of two metallic spheres of radii r1 and r2 connected by a thin wire and switch S as shown in the figure. Initially S is in open position, and the spheres carry charges q1 and q2 respectively. If the switch is closed, the potential of the system is : (a) 1 q1 q2 (b) 1 æçq1 + ç q2 ö÷ ÷ 4πε0 r1 r2 4πε0 çè r1 + r2 ø÷ (c) 1 æçq1 + q2 ö÷ ÷ (d) 1 æçq1 + ç q2 ö÷ ÷ 4πε 0 çè r1 r2 ø÷ 4πε0 çè r1r2 ø÷ 5. Four condensers are joined as shown in the adjoining figure. The capacity of each is 8μF . The equivalent capacity between the points A and B will be : (a) 32μF (b) 2μF (c) 8μF (d) 16μF 6. In the figure shown, what is the potential difference between the points A and B and between B and C respectively in steady state (a) VAB = VBC = 100 V (b) VAB = 75 V, VBC = 25 V (c) VAB = 25 V, VBC = 75 V (d) VAB = VBC = 50 V PHYSICS Topic: ELECTROSTATICS Date: 7. Five identical plates each of area A are joined as shown in the figure. The dis- tance between the plates is d. The plates are connected to a potential difference of V volts. The charge on plates 1 and 4 will be : (a) (c) – ε0 AV . 2ε0 AV d d ε0 AV . – 2ε0 AV d d (b) (d) ε0 AV . 2ε0 AV d d – ε0 AV . – 2ε0 AV d d 8. A network of our capacitors of capacity equal to C1 = C, C2 = 2C, C3 = 3C and C4 = 4C are connected to in a battery as shown in the figure. The ratio of the charges on C2 and C4 is : (a) (c) 22 3 3 (b) 22 7 4 4 (d) 7 9. A capacitor of capacitance 1 F can withstand the maximum voltage 6 kV while a capacitor of capacitance 2.0 F can withstand the maximum voltage 4 kV. If the two capacitors are connected in series, then the two capacitors combined can take up a maximum voltage of : (a) 2.4 kV (b) 5 kV (c) 9 kV (d) 10 kV 10. The energy of uniformly charged solid non conducting sphere of total charge q  radius R is : 1 q2 1 q2 3 1 q2 (a) 4πE0 . R (b) 8πE . R (c) . . (d) None 5 4πE0 R 11. Consider the arrangement of three plates X, Y and Z each of area A and separated d. The energy stored when the plates are fully charged is : (a) (c) ε AV2 2d 2ε AV2 d (b) (d) ε AV2 d 3ε AV2 2d PHYSICS Topic: ELECTROSTATICS Date: 1. (a) 2. (c) Answer Key 3. (b) 4. (b) 5. (c) 6. (c) 7. (a) 8. (b) 9. (c) 10. (c) 11. (b)