**Q.1. What about Gaussâ€™s theorem is not incorrect?**

(a) It can be derived by using Coulomb’s Law

(b) It is valid for conservative field obeys inverse square root law

(c) Gaussâ€™s theorem is not applicable in gravitation

(d) Both (a) & (b)

## Answer

Answer: (d)**Q.2. A uniformly charged conducting sphere of 4.4 m diameter has a surface charge density of 60 Î¼C m ^{â€“2}. The charge on the sphere is**

(a) 7.3 Ã— 10

^{â€“3}C

(b) 3.7 Ã— 10

^{â€“6}C

(c) 7.3 Ã— 10

^{â€“6}C

(d) 3.7 Ã— 10

^{â€“3}C

## Answer

Answer: (d)**Q.3. Gaussâ€™s law is true only if force due to a charge varies as**

(a) r^{â€“1}

(b) r^{â€“2}

(c) r^{â€“3}

(d) r^{â€“4}

## Answer

Answer: (b)**Q.4. A hollow sphere of charge does not have electric field at**

(a) outer point

(b) interior point

(c) beyond 2 m

(d) beyond 100 m

## Answer

Answer: (b)**Q.5. The Gaussian surface**

(a) can pass through a continuous charge distribution.

(b) cannot pass through a continuous charge distribution.

(c) can pass through any system of discrete charges.

(d) can pass through a continuous charge distribution as well as any system of discrete charges.

## Answer

Answer: (a) Gaussian surface cannot pass through any discrete charge because electric field due to a system of discrete charges is not well defined at the location of the charges. But the Gaussian surface can pass through a continuous charge distribution.**Q.6. Charge motion within the Gaussian surface gives changing physical quantity**

(a) electric field

(b) electric flux

(c) charge

(d) gaussian surface area

## Answer

Answer: (a)**Q.7. Select the correct statements from the following.**

I. The electric field due to a charge outside the Gaussian surface contributes zero net flux through the surface.

II. Total flux linked with a closed body, not enclosing any charge will be zero.

III. Total electric flux, if a dipole is enclosed by a surface is zero.

(a) I and II

(b) II and III

(c) I and III

(d) I, II and III

## Answer

Answer: (d)**Q.8. Gauss’s law is valid for**

(a) any closed surface

(b) only regular close surfaces

(c) any open surface

(d) only irregular open surfaces

## Answer

Answer: (a) Gauss’s law is valid for any closed surface, no matter what its shape or size.**Q.9. The electric field due to an infinitely long straight uniformly charged wire at a distance r is directly proportional to**

(a) r

(b) r^{2}

(c) 1/r

(d) 1/r^{2}

## Answer

Answer: (c)**Q.10. Figure shows the part of an infinite plane sheet of charge.**

**Which of the following graphs correctly shows the behaviour of electric field intensity as we move from point O to A.**