Numerical practice X Reflection and Refraction of light

1. An object is placed in front of a concave mirror of radius of curvature 15cm at a distance of (a) 10cm. and (b) 5cm. Find the position, nature and magnification of the image in each case.

2. An object is placed 15cm from a concave mirror of radius of curvature 60 cm. Find the position of image and its magnification?

3. An object is kept at a distance of 5cm in front of a convex mirror of focal length 10cm. Give the position, magnification and the nature of the image formed.

4. An object is placed at a distance of 50cmfrom a concave lens of focal length 20cm. Find the nature and position of the image.

5. The power of a lens is 2.5 dioptre. What is the focal length and the type of lens?

6. What is the power of a concave lens of focal length 50cm?

7. Find the power of a concave lens of focal length 2m.

8. Two lens of power +3.5D and -2.5D are placed in contact. find the power and focal length of the lens combination.

9. A convex lens has a focal length of 20 cm. Calculate at what distance from the lens should an object be placed so that it forms an image at a distance of 40cm on the other side of the lens. State the nature of the image formed?

10. A 10cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 30cm. The distance of the object from the line is 20cm.find the i)position ii)nature and iii) size of the image formed.

11. Find the focal length of a line power is given as +2.0D.

12. With respect to air the refractive index of ice and rock salt benzene are 1.31 and 1.54 respectively. Calculate the refractive index of rock salt with respect to ice.

13. An object 5cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30cm. Find the position of the image, its nature and size.

14. The far point of a myopic person is 150cm in front of the eye. Calculate the focal length and the power of the lens required to enable him to see distant objects clearly.