GATE 2026 IN – Question 63
A current-carrying semiconductor of thickness 0.7 mm is placed in a transverse magnetic field. The measured Hall voltage is 0.9 mV and the current is 6 mA. If the Hall coefficient is $4\times10^{-4}\ \mathrm{m^3/C}$, the value of the incident magnetic field is ________ T. (Rounded off to two decimal places.)
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Correct answer: 0.25 to 0.27
Explanation
The Hall-voltage relation is $V_H=R_HIB/t$. Rearranging and converting all quantities to SI gives $B=V_Ht/(R_HI)=(0.9\times10^{-3})(0.7\times10^{-3})/[(4\times10^{-4})(6\times10^{-3})]$.
This gives $B=0.2625\ \mathrm T$, which rounds to **0.26 T**.