given the mirror formula 1/f=1/v-1/u,f is the focal length of the lens u and v are object and image distance respectively .find f when u and v are 7.5cm and 3.5cm respectively
what, you can't plug in the numbers?
1/f = 1/(7/2) - 1/(15/2)
1/f = 2/7 - 2/15
1/f = (30-14)/105
1/f = 16/105
f = 105/16
To find the focal length (f) using the mirror formula, we need to substitute the values of u (object distance) and v (image distance) into the formula:
1/f = 1/v - 1/u
Given:
u = 7.5 cm
v = 3.5 cm
Substituting the values:
1/f = 1/3.5 - 1/7.5
Now, to find the value of f, we can simplify the equation:
1/f = (7.5 - 3.5)/(7.5 * 3.5)
1/f = 4/26.25
To solve for f, we need to take the reciprocal of both sides of the equation:
f = 26.25/4
Calculating the value:
f ≈ 6.56 cm
Therefore, the focal length (f) of the lens is approximately 6.56 cm.