Title 02. ELECTROSTATIC POTENTIAL AND CAPACITANCE.pdf ✅

BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 02. ELECTROSTATIC POTENTIAL AND CAPACITANCE #QID# 30796 (1.) A metal foil of negligible thickness is introduced between two plates of a capacitor at the centre. The capacitance of capacitor will be (a.) Same (b.) Double (c.) Half (d.) K times ANSWER: a EXPLANATION: (a) The system will be equivalent to series combination of two capacitors of half thickness ie.,each of capacity 2 C ∴ 1 Cs = 1 2c + 1 2c = 1 c or Cs = c ∴capacity remains the same #QID# 30797 (2.) An uncharged sphere of metal is placed inside a charged parallel plate capacitor. The lines of force will look like
BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 (a.) (b.) (c.) (d.) ANSWER: a EXPLANATION: (a) When metal sphere is placed inside a charged parallel plate capacitor, the electric lines of force will not enter the metallic conductor as E = 0inside a charged conductor. Moreover, the surface of a charged conductor is an equipotential surface and hence, electric lines of force are always perpendicular to equipotential surface. #QID# 30798
BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 (3.) In the figure, a proton moves a distance d in a uniform electric field E as shown in the figure. Does the electric field do a positive or negative work on the proton? Does the electric potential energy of the proton increase or decrease? (a.) Negative, increase (b.) Positive, decrease (c.) Negative, decrease (d.) Positive, increase ANSWER: d EXPLANATION: (d) Since, the proton is moving against the direction of electric field so, work is done by the proton against electric field. It implies that electric field does negative work on the proton. Again, proton is moving in electric field from low potential region to high potential region hence, its potential energy increases. #QID# 30799 (4.) A parallel plate capacitor is made by stocking n equally spaced plates connected alternately. If the capacitance between any two plates is x, then the total capacitance is, (a.) nx
BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 (b.) n/x (c.) nx 2 (d.) (n − 1)x ANSWER: d EXPLANATION: (d) (n-1) capacitors are made by n plates and all are connected in parallel because plates are connected alternately. ∴ Total capacitance = (n − 1)x #QID# 30800 (5.) The electric flux for Gaussian surface A that encloses the charged particles in free space. (Given, q1 = −14 nC, q2 = 78.85 nC, q3 = −56 nC) (a.) 103Nm2C −1 (b.) 103CN −1m−2 (c.) 6.32 × 103 Nm2C −1 (d.) 6.32 × 103 CN −1m−2 ANSWER: a EXPLANATION: (a) Total charge enclosed in surface A is