The focal length of a concave mirror, that produces four times larger real image of an object placed at 5 cm distance from the mirror, is------
To determine the focal length of a concave mirror that produces a four times larger real image of an object placed at a distance of 5 cm, we can use the mirror formula:
1/f = 1/v - 1/u,
where:
f is the focal length,
v is the image distance,
u is the object distance.
Given that the image produced is four times larger than the object, we can assume that the image distance (v) is four times the object distance (u). So, v = 4u.
We are also given that u = 5 cm.
Plugging these values into the mirror formula, we can solve for f:
1/f = 1/4u - 1/u
1/f = (1 - 4)/4u
1/f = -3/4u
f = -4u/3
Since f = -4u/3, we can substitute the value of u:
f = (-4 * 5) / 3
f = -20 / 3
The focal length of the concave mirror that produces a four times larger real image of an object placed at 5 cm distance is -20/3 cm.