Calculate the time required for the light to travel a distance of 1.5 x 10^11

Could someone . i have tried to solve myself but my calculation is off

James is trying to prove newton's 2nd law of motion. he tries to move four different objects with different masses, shapes, and sizes from point a to point b. the objects are a toy car, a car, a refrigerator, and a kitchen table. after some experimentation, he finds that force is dependent on the mass of the object, rather than it's size or shape. the object that takes the most force to move is the

Which transition by an electron will release the greatest amount of energy? oa ob oc od