What is the value of B at the instant E reaches its maximum value?

[samee]

Homework Statement

The magnetic field inside a 4.0-cm-diameter superconducting solenoid varies sinusoidally between 8.0 T and 12.0 T at a frequency of 10 Hz.
Pt. 1--> What is the maximum electric field strength at a point 1.5 cm from the solenoid
axis?
Ans.- -> 0.942 V/m
Pt. 2--> What is the value of B at the instant E reaches its maximum value?

Homework Equations

E=cB

The Attempt at a Solution

.942/c=3.14*10^-9

Which is the wrong answer. I can't find any other relationships between E and B! Help please!

 

[vector3]

The link below has a number of relationships like

$$\nabla \times E =- \frac{\partial B}{\partial t}$$

http://en.wikipedia.org/wiki/Maxwell%27s_equations"