2075 Set A Q. No. 106 A Carnot engine has 40% efficiency with a sink at 10°C. By how many degrees should the temperature of the source be increased in order to raise the efficiency to 65%?​

At an oceanside nuclear power plant, seawater is used as part of the cooling system. this raises the temperature of the water that is discharged back into the ocean. the amount that the water temperature is raised has a uniform distribution over the interval from 10° to 25° c. what is the standard deviation of the temperature increase?

1. how to locate the image in converging(concave) mirror and diverging (convex) mirror with salt. 2. how to locate the image in a converging (convex) lens and diverging (concave) lens with salt.

Am i correct on these two physics questions?