Which gives a better measure of the pH: universal PH paper or a pH meter?

Stage in which a star’s outer layers have started to cool and grow outward?

Give a real-world example of an energy transformation that uses two of the following forms of energy: chemical, mechanical, nuclear, gravitational, radiant, electrical, thermal (heat), and/or sound.

1) a light bulb takes in 30 of energy per second. it transfers 3j as use energy. calculate the efficiency. second. it transfers 3j as useful light energy and 27j as heat energy. calculate the efficiency