Multiple choice general knowledge science & technology

The value of thermal voltage (VT)at 300K is

  1. .26 mV

  2. 2.6 mV

  3. 26 mV

  4. It depends upon the applied potential
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

To solve this question, the user needs to know the definition of thermal voltage and its value at room temperature.

Thermal voltage (VT) is the voltage equivalent of the thermal energy of a particle. It is given by the formula:

VT = kT/q

where k is the Boltzmann constant, T is the temperature in Kelvin, and q is the charge of a particle.

At room temperature (300K), the value of VT can be calculated as:

VT = (kT/q) = (1.38 x 10^-23 J/K x 300K) / 1.6 x 10^-19 C

Simplifying this expression, we get:

VT = 0.0259 V = 25.9 mV

Therefore, the answer is:

The Answer is: C. 26 mV

AI explanation

Thermal voltage V_T = kT/q, where k is Boltzmann's constant, T is temperature in Kelvin, and q is the electron charge. At T = 300K (room temperature), V_T = (1.38×10^-23 × 300) / (1.6×10^-19) ≈ 0.02585 V ≈ 25.85 mV, which rounds to about 26 mV -- a widely used reference value in diode and transistor equations (used in the Shockley diode equation and BJT small-signal models). The other options are off by an order of magnitude (0.26 mV, 2.6 mV) and V_T does not depend on applied potential, only temperature, so the last option is also wrong.

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