Consider a convex lens having a thickness d and whose sides have radii of curvature r1 and r2. find the 2*2 matrix describing this lens? what is the change in focal length for the case where the two radii equal r and d=0.1 r compared to the case where the lens thickness is neglected?

How does a circuit breaker protect a refrigerator? a. when the current is too high, a metal strip in the fuse melts and opens the circuit. b. when the resistance is too high , a re-settable which opens a circuit c. when the current is too high , a re-settable switch opens the circuit d. when the resistance is too high a metal strip in the fuse melts and opens the circuit