Complete Question:
Metal sphere A has a charge of − Q . −Q. An identical metal sphere B has a charge of + 2 Q . +2Q. The magnitude of the electric force on sphere B due to sphere A is F . F. The magnitude of the electric force on sphere A due to sphere B must be:
A. 2F
B. F/4
C. F/2
D. F
E. 4F
Answer:
D.
Explanation:
If both spheres can be treated as point charges, they must obey the Coulomb's law, that can be written as follows (in magnitude):
As it can be seen, this force is proportional to the product of the charges, so it must be the same for both charges.
As this force obeys also the Newton's 3rd Law, we conclude that the magnitude of the electric force on sphere A due to sphere B, must be equal to the the magnitude of the force on the sphere B due to the sphere A, i.e., just F.
Answer:
If the frequency of the source is increased the current in the circuit will decrease.
Explanation:
The current through the circuit is given as;
Where;
V is the voltage in the AC circuit
Z is the impedance
Where;
R is the resistance
is the inductive reactance
= ωL = 2πfL
where;
L is the inductance
f is the frequency of the source
Finally, the current in the circuit is given as;
From the equation above, an increase in frequency (f) will cause a decrease in current (I).
Therefore, If the frequency of the source is increased the current in the circuit will decrease.
Sound waves actually travel much faster in water than air, but words and the direction of the noise are distorted.
<span>The question is asking for the reason why water is considered a polar molecule. The correct option is A. Water molecule is a polar molecule because it has one side which is positively charged and the other side is negatively charged. Each molecule of water has two hydrogen atom and one oxygen atom. The slight negative charge near the oxygen atom attract nearby hydrogen atoms from water and the slightly positive charge of the hydrogen atom attract oxygen atom. The attraction set up by these charges are responsible for the polarity of water molecules. </span>
