A student wishes to investigate how the material of which an object is made affects how the object changes temperature. The student will heat objects to a temperature of 50°C, then see how long it takes the objects to cool down to room temperature. For this investigation, it is most important that the student use objects that -

A. are the same size, but made of different materials.
B. will not melt at temperatures above 100°
C. release thermal energy quickly to the environment.
D. are made of metals, since they conduct heat.

A. are the same size, but made of different materials.

Explanation:

When we desire to investigate the temperature changing behaviour of the material then we need to have the two objects respective materials identical in geometry.

As the rate of heat transfer depends on the surface area and the thickness of the object.

B. It must be ensured that there must not be any change in the chemical molecular state and physical molecular state of the material within the range of temperature variation. Here we do not need to heat above 50°C so we're not concerned about the 100°C temperature.

C. Every material has its own thermal property and hence it depends upon the specific heat carrying and transmitting properties which can't be altered and restricted.

D. Every material conducts heat, because heat is the kinetic energy of the molecule at micro level, so we do not necessarily need a metal.

c) up is the direction the magnetic force is acting on the charge.