JKBOSE Physics: Solved Previous Year’s Question Paper for NCERT/CBSE Class 12th Physics Paper Code (XIIRKN16—X)
Short Answer Type Questions
Question: Explain the Conservation of Charge
Answer: Conservation of charge is a law that states that the total amount of electric charge in an isolated system remains constant. This is true for both positive and negative charges and cannot be created or destroyed. This law is closely related to the conservation of energy, as the two are closely intertwined. This law is one of the most fundamental laws of nature, as it applies to all forms of electricity and magnetism.
Question: Explain how you will compare the e.m.f’s of two cells of a potentiometer.
Answer: To compare the e.m.f’s of two cells of a potentiometer, the potentiometer balance method must be used. This involves connecting the two cells in series with a variable resistor (rheostat) and a galvanometer. The resistance of the rheostat is adjusted until the same current flows through both cells, as indicated by the galvanometer. The e.m.f’s of the two cells can then be compared by measuring the potential drop across each cell. If the potential drop across the first cell is greater than that of the second cell, it has a higher e.m.f.
Question: For a given medium, the polarizing angle is 60 degrees. What will be the critical angle for this medium?
Solution
Here, iP=60∘, C=?
μ=taniP=tan60∘=√3
sinC=1μ=1√3=0.5773
C=sin−1 (0.5773) or C= 35∘16′
Question: What is a Junction transistor? Mention its two types. How are they represented?
Answer: A junction transistor is a type of semiconductor device consisting of three terminals, namely the base, collector, and emitter. It is a type of solid-state amplifier used for amplifying and switching electronic signals.
There are two types of junction transistors: NPN and PNP. NPN transistors are represented by arrows pointing away from the emitter and going towards the collector and base, while PNP transistors are represented by arrows pointing towards the emitter and away from the collector and base.
Very Short Answer Type Questions
Question: A 100 Hz a.c. is flowing in a 14 Mh coil. Find the reactance of the coil.
Solution
Here, v = 100 h z , L = 4 m H = 14 × 10 − 3 H
X L = ω L = 2 π v L π × 100 × 14 × 10 − 3 = 8.8 o h m
Question: Draw a labelled diagram showing the course of rays for a simple microscope
Question: why sky wave propagation of electromagnetic waves cannot be used for TV transmission?
Answer: Sky wave propagation of electromagnetic waves is not suitable for TV transmission because this method of propagation is too unpredictable for reliable reception. Sky wave propagation involves the reflection of signals off of the ionosphere, and the ionosphere is constantly changing and can be affected by solar radiation, which makes it difficult to control the path of the reflected signal and can lead to signal fading and interference. In addition, the signal can be reflected on the ground from different angles, resulting in multiple versions of the same signal arriving at different times and locations, which can cause ghosting and other image distortions.
Question: Define binding energy.
Answer: Binding energy is the energy required to break apart a molecule, atom, or other particles into its components. It is the energy that keeps the components together, and it is usually measured in electron volts (eV).
Question: What is a hole? Which type of doping creates a hole?
Answer: A hole is an absence of electrons in a material. A type of doping known as p-type doping creates a hole by introducing an impurity that has fewer electrons than the host material, leaving a shortage of electrons.
Objective Type Questions
Question: The electromagnetic waves used in telecommunication are——
Answer: Radio Waves.
Question: One Photon of light is capable of ejecting one electron only True/False
Answer: True
Question: Draw a p-n junction with forward bias
