Five charges, q each are placed at the corners of a regular pentagon of side ‘ a ’ as shown. What will be the electric field at O if the charge from one of the corners (say A ) is removed?

When charge q is placed at all corners of regular polygon then due to symmetry electric field E ' at O is zero ∴ E ' = 0 Now charge q is removed from corner A therefore, net charge at A becomes zero. Or we can say that charges at corner A are + q , - q (net charge is zero) We know electric field at O due to other four corner and due to charge + q at corner A is zero. Hence, net electric field E at O is due to charge - q at A . ∴ E = 1 4 πε 0 q r 2 along OA where, r = a 2 sin 36 ° is the radius of pentagon

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 1

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A capacitor of $4 µ F$ is connected in a circuit as shown. The internal resistance of the battery is $0.5 Ω$ . The amount of charge on the capacitor plates will be

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Important Questions on Sample Paper II

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 2

Two charged particles traverse identical helical paths in a completely opposite sense in a uniform magnetic field

\vec{B} = B_{0} \hat{k}

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 3

A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease? Explain.

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 4

Professor C.V Raman surprised his students by suspending freely a tiny light ball in a transparent vacuum chamber by shining a laser beam on it. Which property of EM waves was he exhibiting? Give one more example of this property.

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 5

A passenger in an aeroplane shall

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NCERT Exemplar Physics - Class 12>Chapter 17 - Sample Paper II>SAMPLE PAPER>Q 6

What is the shape of the wavefront on earth for sunlight?

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