Problem 10.14. A convex lens forms image of an object on a fixed screen 20 cm from the lens. On moving the lens 60 cm towards the object, the image is again formed on the screen. What is the focal length of the lens? Geometrical Optics problem 14. Sindh Textbook Board (stb) problems

  

THE SCOPE OF PHYSICS 

(PROBLEMS)

1. Find the area of a rectangular plate having length (21.3 ± 0.2)cm and width (9.80 ± 0.10)cm.

2. Calculate (a) the circumference of a circle of radius 3.5cm and (b) area of a circlue of radius 4.65cm.

3. Show that the expression S=Vit + 1/2at^2 is dimensionally correct, when S is a co-ordinate and has unit of length, vi is velocity, a is acceleration, and t is time.

4. Suppose the displace of a particle is related to a time according to expression S=ct^3. What are the dimensions of the constant c.

5. Estimate the number of litres of gasoline used by all Pakistan's car each year given: No of cars in Pakistan = 500000. Average distance travelled per year by each car = 16000km gasoline consumption 6km/litre.