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The maximum value of B in an electromagnetic wave is equal to 6×10⁻⁸ T. Thus the maximum value of E is ______.

Asked in GSEB Board July 2018 · E0 = cB0 and E/B = c

• (1) 2 V m⁻¹
• (2) 18 V m⁻¹
• (3) 2.5 V m⁻¹
• (4) 6 V m⁻¹

Step-by-step solution

Why the other options are wrong

• (1) comes from dividing the mantissas, 6/3=2, and letting the powers of ten look after themselves. The relation multiplies by c, it does not divide.
• (3) comes from no single slip produces 2.5 V m⁻¹. Sanity check: E₀=cB₀=3×10⁸×6×10⁻⁸=18 V m⁻¹, more than seven times this.
• (4) comes from copies the mantissa of the given B₀ straight across; the factor c was never applied at all.

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