Answer:
Time period for Simple pendulum, 
Explanation:
The Simple Pendulum
Consider a small bob of mass 
is tied to extensible string of length 
that is fixed to rigid support. The bob is oscillating in the plane about verticle.
Let 
is the angle made by string with vertical during oscillation.
Vertical component of the force on bob, 
Negative sign shows that its opposing the motion of bob.
Taking as very small angle then, 
Let 
is the displacement made by bob from its mean position ,
then, 
so, 
........(1)
Since, pendulum is in hormonic motion,
as we know, 
where 
is the constant and 
.........(2)
From equation (1) and (2)
Since, 
Yes the correct answer was
A) The box will not move.
One charge is enough in order to have an electric field.
In fact, every charge generates an electric field: for example, the electric field generated by a single point positive charge is radial, as shown in the attached figure. More complicate electric field configurations can be obtained adding charges or using more complicate charge distributions, but one charge is enough to have an electric field.
Answer: The second option.When
the current flows up the wire, the magnetic field flows out on the left
side of the wire and in on the right side of the wire.Explanation:
The first figure that I copy here with is the figure corresponding to this question.
The thumb is pointing upward.
The rule is that the thumb aims to the direction of the flow of current and the other fingers give the field lines.
The second figure that I attach is a free image from internet and it shows the direction of both the current and the fiedl lines.
So, the conclusion is that
the current goes upward the wire and the field lines go out of the paper (screen) for the points to the left of the wire and in on the right side of the wire.
