Answer: B
According to Coulomb: Like charges repel each other; unlike charges attract. Thus, two negative or positives charges repel one another, while a positive charge attracts a negative charge.
We see that the only diagram who shows two like charges and their Electromagnetic Forces is B
Answer with explanation:
We know that when we weigh ourselves on a scale the scale measures the Reaction force that acts between the scale and the person who wishes to determine his weight.
The free body diagram of the person on a weighing scale is represented in the attached figure.
As we can see for equilibrium
where,
R is the reaction force between the support and the person
W is the weight of the person which by definition is the force that the earth exerts on the person.
Thus according to the above relation we conclude that that support force of the scale is equal to the gravitational force in magnitude but is opposite in direction.
Answer: Electric current
Explanation :
The direction of the magnetic field produced by an electric current will change when the direction of the electric current changes.
For example :
If a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).
Let the field lines are in the clockwise direction and when the direction of current is reversed then the direction of the magnetic field is in anticlockwise direction.
To thaw a product requires it to undergo the process of
being subjected to latent heat of fusion. In this process, there is no change
in temperature however there is a change of phase from solid to liquid. What is
being thawed here actually is the frozen ice into liquid water which is in the
vegetables.
From the references, the latent heat of fusion of water
is:
Δ H = 333.55 kJ / kg
Therefore the amount of heat required to thaw the frozen
vegetable is:
Heat required = Δ H * m
Heat required = (333.55 kJ / kg) (0.450 kg)
Heat required = 150.10 kJ
In 1 kcal there is 4.184 kJ, therefore:
Heat required = 150.10 kJ (1 kcal / 4.184 kJ)
<span>Heat required = 35.87 kcal</span>