Question
A solid metallic sphere has a charge +3Q. Concentric with this sphere is a conducting spherical shell having charge –Q. The radius of the sphere is a and that of the spherical shell is b (b > a). What is the electric field at a distance R (a < R < b) from the centre?
Q / (2\pi ε₀R)
3Q / (2\pi ε₀R)
3Q / (4\pi ε₀R²)
4Q / (4\pi ε₀R²)
To find the electric field at a distance (where ), we use Gauss's Law. We construct a spherical Gaussian surface of radius concentric with the system.
According to Gauss's Law: .
The charge enclosed () by this surface is the total charge on the inner sphere, which is . The outer shell's charge () lies outside the Gaussian surface and does not contribute to the electric flux through it (the field inside a uniformly charged spherical shell due to the shell itself is zero).
Thus, . Solving for , we get .
This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from ELECTRIC CHARGES AND FIELDS. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.
More ELECTRIC CHARGES AND FIELDS Questions
Two identical charged spheres suspended from a common point by two massless strings of lengths l are initially at a distance d (d << l) apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity v. Then v varies as a function of the distance x between the spheres, as:
Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude $17.0 \times 10^{-22} \, \text{C/m}^2$. The electric field between the plates is:
Two point charges $q_A = 3 \, \mu\text{C}$ and $q_B = -3 \, \mu\text{C}$ are located $20 \, \text{cm}$ apart in a vacuum. The electric field at the midpoint $O$ of the line $AB$ joining the two charges is:
The electric field in a certain region is acting radially outward and is given by E = Ar. A charge contained in a sphere of radius 'a' centered at the origin of the field will be given by:
The electric field due to a uniformly charged solid sphere of radius R as a function of the distance from its centre is represented graphically by -
Four-point +ve charges of the same magnitude (Q) are placed at four corners of a rigid square frame as shown in the figure. The plane of the frame is perpendicular to Z-axis. If a –ve point charge is placed at a distance z away from the above frame (z<<L) then
Shown below is a distribution of charges. The flux of electric field due to these charges through the surface S is:
Two point charges A and B, having charges +Q and −Q respectively, are placed at a certain distance apart and the force acting between them is F. If 25% charge of A is transferred to B, then the force between the charges becomes:
Why 32,000+ students choose TopperSquare
15,000+ Chapter MCQs
Physics, Chemistry, Biology — chapter-wise, topic-wise practice
AI Performance Analytics
Know your weak topics. Get a personalised study plan.
Full NEET Mock Tests
180 questions, timed, with detailed score analysis
PYQ Sets 2010–2024
15 years of past papers with solved explanations
No credit card · 30-second signup · Free forever plan included
This neet physics practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice physics sets →
Sign in to save your score, view detailed analytics, and bookmark tough questions for revision.
Sign In / Join FreeChapter-wise practice sets
Identify weak areas instantly
Step-by-step logic for every question