Answer: Option C) Rinse the affected area with cool water for 10-15 minutes.
Explanation:
Once exposed to burns, whether chemical or heat, rinse the affected area of the body with cool water, as water is known to dissolve all burning particles attached to the skin, and cool off the blood vessels lying beneath the burned surface.
Unlike other options provided, rinsing affected area with cool water is the best first aid for skin burns
Earthquakes along the San Andreas fault in California.
<u>Explanation</u>:
- When the two plates collide with each other, earthquakes occur. The contact between them makes this earthquake possible. The contact forces are responsible for the earthquakes as there is contact between two plates.
- The gravitational force is a force that is responsible for elevated tides happening on the east coast or the Jupiter's moons to remain in orbit. But this is not a contact force as there is no contact between them
- Moreover, Without any contact, the magnetic force is a non-contact as it attracts the pins from a distance.
Answer: b. 
is positive and 
is positive.
Explanation:-
As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of 
in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e. is positive.
The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e. is positive.
In order of reactivity: magnesium, iron, copper, silver
