magnetic field due to a finite straight conductor is given by

here since it forms an equilateral triangle so we will have

also the perpendicular distance of the point from the wire is

now from the above equation magnetic field due to one wire is given by



now since in equilateral triangle there are three such wires so net magnetic field will be

It is true that Gustav Theodor Fechner was the finder of <span>psychophysics. </span>
1. 
Explanation:
We have:
voltage in the primary coil
voltage in the secondary coil
The efficiency of the transformer is 100%: this means that the power in the primary coil and in the secondary coil are equal

where I1 and I2 are the currents in the two coils. Re-arranging the equation, we find

which means that the current in the secondary coil is 14% of the value of the current in the primary coil.
2. 5.7 V
We can solve the problem by using the transformer equation:

where:
Np = 400 is the number of turns in the primary coil
Ns = 19 is the number of turns in the secondary coil
Vp = 120 V is the voltage in the primary coil
Vs = ? is the voltage in the secondary coil
Re-arranging the formula and substituting the numbers, we find:

Answer and Explanation:
The ball is bouncing to a height of 1/3 of its previous height this is a type of geometric sequence the total distance can be found by the sum of geometric sequence
For example let the initial height is 243 fit
After one bounce it will reach 243/3 =81 feet
After second bounce 81/3=27 feet
After third bounce 27/3 =9 feet
After fourth bounce 9/3 =3 feet
So a sequence is formed that is 243,81,27,9,3..........
Here 
Sum of infinite GP = 
From this formula we can find the total distance traveled by the ball