The conditions for the interference of waves are:

a. the waves must be coherent and monochromatic

b. varying phase difference and monochromatic light

c. varying phase difference and multiple wavelength

d. the waves must be coherent and multiple wavelength

Calibrating equipment can reduce the effect of:

a. both random errors and systematic errors

b. neither random nor random errors

c. random errors

d. systematic errors

The direction of upthrust and weight acting on an object act in the:

a) same direction

b) opposite direction

c) upward

d) downward

In elastic collisions:

A. kinetic energy is not conserved

B. objects bounce off each other

C. energy is conserved

D. the relative speed is uncharged