Question

11) A rectangular coil of dimensions 20cm by 15cm lies with its plane parallel to a magnetic field of
0.5W/$m2
. The coil, carrying a current of 10A experiences a torque of 4.5Nm in the field. How many loops has the coil?
a) 100
b)60
c) 30
d) 20

12) An electric feild of 50kV/m is perpendicular to a magnetic field 0.25T. What is the velocity of a charge whose initial of motion is perpendicular to both fields and which passes through the fields undeflected?

a) 3×10
m/s

b) 2×10
m/s

c) 4×10
m/s

d) 5×10
m/s