CBSE Class 12th Physics Solved Guess Paper: 2018

Mayank Uttam

Updated: Jan 18, 2018 17:55 IST

CBSE Class 12 Date Sheet 2018: Analysis and Exam Preparation Tips

Due to this reason, we have provided a completely solved Guess Paper for Class 12 Physics board exam 2018.This solved paper is developed by our subject experts at Jagranjohs.com. Our subject experts have analysed previous 5 years’ papers and pointed out that some concepts from Class 12th NCERT textbooks are frequently asked in board exams, every year. This solved guess paper is basically based on such important concepts. After going through the complete paper you can easily learn about these important concepts. In case of any doubt, you can go through these topics again from Class 12 Physics NCERT textbooks (Part I and Part II)  

CBSE Class 12 Physics Sample Paper: 2018

In this solved Guess Paper, there are 5 sections (i.e., Section A, Section B, Section C, Section D and Section E)

• Section A contains question number 1 to 5 (very Short Answer type questions of one mark each)

• Section B contains question number 6 to 10 (Short Answer type I questions of two marks each)

• Section C contains question number 11 to 22 (Short Answer type II questions of three marks each)

• Section D contains question number 23 (value Based Question of four marks)

• Section E contains question number 24 to 26 (Long Answer type questions of five marks each)

Internal choices are present in short answer types questions and long answer type questions (According to latest CBSE Class 12 Physics Examination Pattern 2017 – 2018)

CBSE Class 12th Physics Notes: All Chapters

Salient features of the Solved Guess Paper are:

• Strictly follows latest CBSE Class 12^th Physics syllabus

• Based on latest examination pattern

• Blueprint of this guess paper is almost similar to the latest CBSE Cass 12 Physics Sample Paper

• Focuses upon topics from which questions are likely to be asked

• Offers detailed solutions for each and every question

• Perfect for practice and revision

Some questions from the solved guess paper are given below:

Question: Define current sensitivity of a galvanometer?

Answer:

Current sensitivity of a galvanometer is defined as deflection produced in the galvanometer when a unit current flows through it.

Question: Why is soft iron core preferred for making the core of a transformer?

Answer:

As, the area of hysteresis loop for soft iron is very small so, energy dissipated per unit volume per cycle of magnetisation is small.

Question: Write two ways by which the range of transmission can be increased?

Answer:

Range of transmission of T.V. signal can be increase

• By increasing the power of transmitting signal from TV station

• By increasing the heights of transmitting and receiving antenna

Question: What is meant by ‘half-life’ of a radioactive element? What percentage of a given mass of a radioactive substance will be left undecayed after four half lives?

Answer:

The time interval in which the number of atoms of a radioactive element decays to one-half of its initial value is called half-life of the element.           

If N_o is the initial quantity of radioactive element, then the quantity N of the element left after n half-live is given by: N = N_o(1/2)ⁿ.

The amount of substance left after 4 half lives can be given as:

N = N_o(1/2)⁴ = N_o/16 or 6.25% of initial value.

Question:

Arrange the following electromagnetic radiations in ascending order of their frequencies:
(i) Microwaves
(ii) Radio waves
(iii) X-rays
(iv) Gamma rays
Write two uses of any two of these.

Answer:

Given electromagnetic radiations in ascending order of their frequencies are: Radio waves, microwaves, ultraviolet rays, X-rays and gamma
rays.
Uses of Electromagnetic Spectrum
(i) Gamma-rays are highly penetrating. They can penetrate thick iron blocks. Due to high energy, they are used to produce nuclear reactions. g-rays are produced in nuclear reactions. In medicine, they are used to destroy cancer cells.
(ii) X-rays are used in medical diagnostics to detect fractures in bones, tuberculosis of lungs,
presence of stone in gallbladder and kidney. They are used in engineering to check flaws in
bridges. In physics X-rays are used to study crystal structure.

Question: Amit is a resident of Tamil Nadu was all set to leave everything and shift to another place in view of the decision of Government to start nuclear thermal power plant at Tamil Nadu. His granddaughter Rashi, a science student was really upset on the ignorant decision of her grandfather. She could finally convince him not to shift, since adequate safety measures to avoid any nuclear mishap have already been taken by the Government before starting nuclear thermal power plants.

(i) What is the value displayed by Rashi in convincing her grandfather?

(ii) What is the principle behind working of nuclear reactor?

(iii) What are the main components of nuclear reactor?

(iv) Why is heavy water used as moderator?

Answer:

(i) Rashi is attached to her native place.

(ii) A Nuclear reactor works on the principle of nuclear fission

(iii) Moderator, Cadmium rods

(iv) Heavy water (D₂O) is used to slow down the speed of fast moving neutrons.

Question: (a) Explain the meaning of the term mutual inductance. Consider two concentric circular coils, one of radius r₁ and the other of radius r₂(r₁<r₂) placed coaxially with centres coinciding with each other. Obtain the expression for mutual inductance of the arrangement. (b) A rectangular coil of area A, having number of turns N is rotated at ‘f’ revolution per second in a uniform magnetic field B, the field being perpendicular to the coil. Prove that the maximum emf induced in the coil is 2πf NBA.

.

.

.

Other questions and solutions are available in the Guess Paper's PDF

Get the Complete Class 12th Physics Solved Guess Paper for CBSE Board Exam 2018