Answer:
The correct option is (C).
Explanation:
Electric current can be direct or alternating.
The direct current flows only in one direction. It is unidirectional.
The alternating current or an C current reverse its direction periodically.
So, the correct statement regarding the alternating current is (c) i.e. Electrons reverse direction periodically.
Answer:
If the temperature of the colder object rises by the same amount as the temperature of the hotter object drops, then <u>the specific heats of both objects will be equal.</u>
Explanation:
If the temperature of the colder object rises by the same amount as the temperature of the hotter object drops when the two<u> objects of same mass</u> are brought into contact, then their specific heat capacity is equal.
<u>We can prove this by the equation of heat for the two bodies:</u>
<em>According to given condition,</em>


<em>when there is no heat loss from the system of two bodies then </em>


- Thermal conductivity is ultimately affects the rate of heat transfer, however the bodies will attain their final temperature based upon their mass and their specific heat capacities.
The temperature of the colder object will rise twice as much as the temperature of the hotter object only in two cases:
- when the specific heat of the colder object is half the specific heat of the hotter object while mass is equal for both.
OR
- the mass of colder object is half the mass of the hotter object while their specific heat is same.
Answer:
The kinetic energy of the cell phone is 9J
Explanation:
The kinetic energy is the energy possessed by a body by virtue of motion.
The kinetic energy is expressed as
KE= 1/2m(v)²
Given data
Mass of cell phone m= 80g--to kg=80/1000= 0.08kg
Velocity of cell phone v= 15m/s
Substituting our given data we have
KE= 1/2*0.08(15)²
KE= (0.08*225)/2
KE=18/2
KE= 9J
Answer:
J = Δp
Explanation:
The impulse-momentum theorem says that the impulse J is equal to the change in momentum p.
J = Δp