# WBJEE: Important Questions and Preparation Tips – Electrostatics

In this article, you will get to know important concepts, formulae and previous year questions of WBJEE examination related to chapter Electrostatics that will help you in your preparation for WBJEE Examination 2018. These notes are prepared by Subject Experts after the analysis of previous year paper of WBJEE Examination.

Created On: Oct 24, 2017 15:24 IST
WBJEE 2018: Electrostatics

Electrostatics is one of the important chapters in the syllabus of WBJEE Entrance Examination 2018. About 2-4 questions are being asked from this chapter in WBJEE examination. Find chapter notes of chapter Electrostatics for WBJEE Entrance Examination 2018.

These chapter notes include important topics like electric charge, Coulomb’s law, electric field, potential due to a point charge, potential due to a system of charges, relation between field and potential, electric dipole, electric flux, Gauss’s law, the parallel plate capacitor etc.

The concept given in these notes is in concise form and can be used for revision before WBJEE entrance examination. These notes will help students to save their precious time and to cover maximum syllabus in minimum time just before examination.

West Bengal Joint Entrance Examination (WBJEE) is a state level common entrance test organized by West Bengal Joint Entrance Examinations Board for admission to the Undergraduate Level Engineering and Medical Courses through a common entrance test in the State of West Bengal.

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Important Concepts:

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Some previous years solved questions are given below:

Question 1:

Three capacitors, 3μF, 6μF and 6μF are connected in series to a source of 120V. The potential difference, in volts, across the 3μF capacitor will be

(A) 24

(B) 30

(C) 40

(D) 60

Solution 1:

C= 3 μF

C= 6 μF

C= 6 μF

Hence, the correct option is (D).

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Question 2:

A parallel plate capacitor is charged an then disconnected from the charging battery. If the plates are now moved farther apart by pulling at them by means of insulating handles, then

(A) the energy stored in the capacitor decreases

(B) the capacitance of the capacitor increases

(C) the charge on the capacitor decreases

(D) the voltage across the capacitor increases

Solution 2:

So, the voltage increases as the plates are now moved farther apart by pulling at them by means of insulating handles.

Hence, the correct option is (D).

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Question 3:

Consider two concentric spherical metal of radi r1 and r2 (r2 > r1). If the outer shell has a charge q and the inner one is grounded, the charge on the inner shell is

Solution 3:

Hence, the correct option is (C).

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Question 4:

A 5 µF capacitor is connected in series with a 10 µF capacitor. When a 300 Volt potential difference is applied across this combination, the energy stored in the capacitors is

(A) 15 J

(B) 1.5 J

(C) 0.15 J

(D) 0.10 J

Solution 4:

Let us assume that,

C1=5 µF

C2=10µF

Hence, the correct option is (C).

Important Questions and Preparation Tips – Simple Harmonic Motion

Question 5:

Solution 5:

Hence, the correct option is (A).