(i) Write the function of three segments of a transistor.
(ii) Draw the circuit diagram for studying the input and output characteristics of n-p-n transistor in common emitter configuration. Using the circuit, explain how input, outpput characteristics are obtained.

(a) Calculate the distance of an object of height h from a concave mirror of radius of curvature 20 cm, so as to obtain a real image of magnification 2. Find the location of image also.
(b) Using mirror formula, explain why does a convex mirror always produce a virtual image.

(i) State Bohr's quantization condition for defining stationary orbits. How does de Broglie hypothesis explain the stationary orbits?
(ii) Find the relation between the three wavelengths 𝜆₁, 𝜆₂ and 𝜆₃ from the energy level diagram shown below.

Draw a schematic diagram of reflectiing telescope showing how rays coming from a distant object are received at eye-piece. Write its two important advantages over a refracting telescope.

Meeta's father was driving her to school . At the traffic signal she noticed that each traffic light was made of many tiny lights instead of a single bulb. When Meeta asked this question to her father, he explained the reason for this.
Answer the following questions based on above information:
(i) What were the values displayed by Meeta and her father?
(ii) What answer did Meeta's father give?
(iii) What are the tiny lights in traffic signals called and how do these operate?

(i) An a.c. source of voltage V = V∘sin ωt is connected to a series combination of L, C and R. Use the phasor diagram to obtain expressions for impedance of the circuit and phase angle between voltage and current. Find the condition when current will be in phase with the voltage. What is the circuit in this condition called?
(ii) In a series LR circuit Xᴸ = R and power factor of the circuit is P₁. When capacitor with capacitance C such that Xᴸ = Xᴄ is put in series, the power factor becomes P₂. Claculate P₁/P₂.

(i) Write the function of a transformer. State its principle of working with the help of a diagram. Mention various energy losses in this device.
(ii) The primary coil of an ideal step up transformer has 100 turns and trasnformation ratio is also 100. The input voltage power are respectively 220 V and 1100 W. Calculate
(a) number of turns in secondary
(b) current in primary
(c) voltage across secondary
(d) current in secondary
(e) power in secondary

(i) Define the term drift velocity.

(ii) Why alloys like constantan and manganin are used for making standard resistors?

State the principle of working of a potentiometer.