Image Formation by a Convex Mirror
- A convex mirror always forms a virtual, erect, and diminished image behind the mirror.
- The image is always located between the pole and focus of the mirror.
Derivation of the Mirror Equation
Using the sign convention:
- The mirror formula is given by: \[ \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \] where:
- \( f \) = Focal length of the mirror
- \( u \) = Object distance
- \( v \) = Image distance
For a convex mirror, \( f \) and \( v \) are positive, while \( u \) is negative. Thus, the mirror equation holds for both concave and convex mirrors.
A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).