Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by _{${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}} , {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}} \mathrm{and} {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Ge}}$} respectively. Which one of the following relationships is true in their case?

• ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}} > {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{si}}$

• ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}} = {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$

• ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}} < {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Ge}}$

• ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}} > {\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$

A working transistor with its three legs marked P, Q and R are tested using a multimeter. No conduction is found between P and Q. By connecting the common (negative) terminal of the multimeter to R and the other (positive) terminal of P or Q, some resistance is seen on the multimeter. Which of the following is true for the transistor?

In the circuit below, A and B represent two inputs and C represents the output. The circuit represents

If in a p-n junction diode, a square input signal of 10V is applied as shown Then the output signal across RL will be 

Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?

A thermocouple is made from two metals, Antimony and Bismuth. If one junction of the couple is kept hot and the other is kept cold then, an electric current will

A solid which is transparent to visible light and whose conductivity increases with temperature is formed by

In a common base mode of a transistor, t collector current is 5.488 mA for an emit current of 5.60 mA. The value of the base current amplification factor (β) will be

The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows