Question

magnetic field = 0.479 t
wire length = 1.78 m
relative speed =
emf = 4.50 v
5.28 m/s
20 m/s
0.920 m/s
60 m/s
magnetic field = 0.070 t
wire length = 1.42 m
relative speed =
emf = 6.00 v
20 m/s
5.28 m/s
0.920 m/s
60 m/s

Explanation:

Step1: Recall the formula for EMF

The formula for the electromotive force (EMF) induced in a moving wire in a magnetic field is $EMF = B\times l\times v$, where $B$ is the magnetic field, $l$ is the length of the wire, and $v$ is the relative speed. We need to solve for $v$, so $v=\frac{EMF}{B\times l}$.

Step2: Substitute values for the first set of data

Given $B = 0.479T$, $l = 1.78m$, $EMF=4.50V$. Then $v=\frac{4.50}{0.479\times1.78}$.
Calculate $0.479\times1.78 = 0.85262$.
Then $v=\frac{4.50}{0.85262}\approx5.28m/s$.

Step3: Substitute values for the second set of data

Given $B = 0.070T$, $l = 1.42m$, $EMF = 6.00V$. Then $v=\frac{6.00}{0.070\times1.42}$.
Calculate $0.070\times1.42=0.0994$.
Then $v=\frac{6.00}{0.0994}\approx60m/s$.

Answer:

For the first part: $5.28m/s$.
For the second part: $60m/s$.