An unpolarized light wave is traveling along positive X-axis. The electric field vector in the beam vibrates in the direction of
A. Positive Y-axis definitely
B. Negative X-axis
C. Positive X-axis
D. Y or Z-axis
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Which one of the following research methods can show cause and effect

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.