focal length of a concave mirror

Question 1

how was an approximate value for the focal length found?

Answer 1

focus a distant object onto a screen using the mirror. measure the distance between the mirror and the screen for the approx. focal length

Question 2

what was the advantage of finding the approximate value for the focal length?

Answer 2

allows you to set up the experiment with the object outside the focal length{gives a real image}

Question 3

describe how the student found the position of the image

Answer 3

set up as show in the diagram. move the screen until the clearest sharpest image of the object is projected onto the screen. measure the distance from the mirror to the screen to find the image distance

Question 4

formula to calculate focal length

Answer 4

1/f=1/u+1/v

Question 5

give two precautions that should be taken when measuring the image distancee

Answer 5

1. avoid parralax error
2. measure from the centre of mirror
3. find the clearest sharpest image

Question 6

why did the students repeat the experiment

Answer 6

to increase the accuracy of the results

Question 7

what is plotted on the x and y axes for the graph for this experiment

Answer 7

1/u and 1/v

Question 8

how would the graph be used to calculate the focal length of the mirror

Answer 8

calculate values of 1/u and 1/v. plot these points on the graph and draw a best fit line. where the lines crosses the x axis and y axis gives a value for 1/f . get and average of the two and find f