Physics

Q.

A concave mirror produces three times magnified (enlarged) real image of an object placed at $10cm$ in front of it. Where is the image located?

Q. Two point charges q1 and q2 of magnitude 10 raise to -8C and -10 raise to -8C, respectively are placed 0.1m apart. Calculate the electric field at point A B and C as shown in figure.

Q.

What is resource planning ? Why is it essential? Explain any two reasons.

Q.

Classify resources on the basis of origin and availability.

Q.

Difference between real and virtual image

Q.

Under what condition is the magnitude of average velocity of an object equal to its average speed?

Q.

What is the Working Principle of a Transformer?

Q. A person cannot see beyond 2 m. If he has to read a signboard 4 m away, then the power of the lens required is

1. 0.25 D
2. -0.25 D
3. 0.75 D
4. -0.75 D

Q.

Convert the following temperatures to the Celsius scale.

(a) $293\mathrm{K}$

Q.

An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of a focal length of 18 cm. At what distance from the mirror should a screen be placed so that a sharply focused image can be obtained? Find the size and the nature of the image.

Q.

Discuss any three problems caused by indiscriminate use of natural resources.

Q. Difference between centrifugal force and centripetal force

Q.

In the derivation of electric field due to an electric dipole on an equatorial line, why do we put cos $\theta =\frac{a}{\sqrt{2}+r^2}$

Q.

Give the sign convention in concave and convex mirrors.

Q. Two point charges of +2 μC and +6 μC repel each other with a force of 12 N. If each is given an additional charge of – 4 μC, what will be the new force?

Q. The ratio of electric force and gravitational force between a proton and an electron is K e^2 / G memp ≅ 2.4 × 10^39

Q. Which of the following graphs is incorrect for a conductor at a given temperature?

1. 
2. 
3. 
4. 

Q. An infinite line charge produces a field of 18*10(to the power of 10) N/C at a distance of 1m. The linear charge density is?

Q. Two identical small bodies each of mass m and charge q are suspended from two strings each if length l from a fixed point. This whole system is taken into an orbiting artificial satellite, then find the tension in strings

Q.

A charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium, if $q$ is equal to

1. $-\frac{Q}{2}$

2. $-\frac{Q}{4}$

3. $+\frac{Q}{4}$

4. $+\frac{Q}{2}$

Q.

A convex mirror used on automobile has 3 m radius of curvature. If a bus is located at 5m from this mirror, find the position and size of the image

Q.

What are the 7 electromagnetic waves in order?

Q.

At what distance from a concave mirror of focal length 10 cm should an object 2 cm long be placed in order to get an erect image 6 cm tall ?

Q.

Define the pole, the center of curvature, the radius of curvature, principal axis, aperture, focus, and focal length of a spherical mirror.

Q.

A convex mirror used as rear view mirror on an automobile has a radius of curvature of 3.00 m. If a bus is located at 5.00 m from this mirror, find the position, nature and size of the image.

Q.

When an object is placed 20 cm from a concave mirror, a real image magnified three times is formed. Find : (a) the focal length of the mirror. (b) Where must the object be placed to give a virtual image three times the height of the object ?

Q.

A concave lens of focal length $15cm$ forms an image $10cm$ from the lens. How far is the object placed from the lens? Draw the ray diagram.

Q.

How to convert 300 Kelvin into celsius?

Q.

When an object is placed at a distance of 50 cm from a concave spherical mirror, the magnification produced is, -$\frac{1}{2}$ . Where should the object be placed to get a magnification of, - $\frac{1}{5}$ ?

Q.

Question 7
We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.