HELP HURRY PLEASE According to the law of reflection, if angle of incidence is 50, what is angle of reflection?
A. 45
B. 50
C. 25
D. 100

In a vernier instrument the main scale is in 1/2 mm divisions .vernier is made by redividing 19 such divisions into 20 equal parts. calculate the least count of the instrument.

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.