It requires 350 joules to raise a certain amount of a substance from 10.0°c to 30.0°c. the specific heat of the substance is 1.2 j/g°c.

I'll assume you are looking for the mass of the object, since that is the missing piece of the puzzle.

The important equation for heat and energy is

Energy = mass × specific heat × change in temperature

Things we know:
Energy needed is 350 J.
Specific heat = 1.2 J/g°C
Temp. change = (30-20)°

Now we just need to plug those in and rearrange the formula to find the mass!

350 = mass × 1.2 × 10

Your answer is c. explanation: plasma  is the fourth state of matter, derived from the gaseous state of matter.  plasma  can contain free  electrons  and/or  ions. while  plasma is never neutral, it can either be positively or negatively charged.  gases, however, are electrically neutral.

Wavelength divides in half and speed stays the same.