There are three subjects i.e., Physics, Chemistry and Mathematics in JEE Main entrance examination. All subjects are important to secure good marks in the examination. Engineering aspirants have already covered most of the syllabus of all the subjects.
Now, aspirants should focus on solving more and more practice paper to increase their speed and accuracy. It is very important to get familiar with the pattern of the examination before appearing for the final examination.
In this article, engineering aspirants who are going to appear for JEE Main entrance examination 2018 will find Solved Practice Paper of Physics based on the latest pattern and syllabus.
JEE Main Physics Syllabus: 2017 – 2018
About the paper:
1. This paper consists of 30 questions from easy to tough level.
2. It is prepared by experienced Subject Experts of Physics at Jagranjosh.
3. They have included questions from different topics like Gravitation, Electric Charges and Fields, Electrostatic Potential and Capacitance, Current Electricity, Light, Laws of Motion, Properties of Bulk Matter etc.
4. Solutions of all the questions in this practice paper are explained in a detailed manner.
Question
A speech signal of 3 kHz is used to modulate a carrier signal of frequency 1 MHz, using amplitude modulation. The frequencies of the side bands will be
(a) 1.003 MHz and 0.997 MHz
(b) 3001 kHz and 2997 kHz
(c) 1003 kHz and 1000 kHz
(d) 1 MHz and 0.997 MHz
Sol. (a)
Given, frequency of carrier signal is wc = 1 MHz
and frequency of speech signal = 3 kHz
= 3 × 10-3MHz
= 0.003 MHz
Now, we know that,
Frequencies of side bands = (wc ± wm)
= (1 ± 0.003)
= 1.003 MHz and 0,997 MHz
Question
Hole is
(a) an anti-particle of electron
(b) a vacancy created when an electron leaves a covalent bond
(c) absence of free electrons
(d) an artificially created particle
Sol. (b)
The concept of hole describes the lack of an electron at a position where one could exist in an atom or atomic lattice. If an electron is excited into a higher state, it leaves a hole in its old state.
Question
An electron is projected with uniform velocity along the axis of a current carrying long solenoid. Which of the following is true?
(a) The electron will be accelerated along the axis
(b) The electron path will be circular about the axis
(c) The electron will experience a force at 45° to the axis and hence execute a helical path
(d) The electron will continue to move with uniform velocity along the axis of the solenoid
Sol. (d)
Magnetic Lorentz force electron is projected with uniform velocity along the axis of a current carrying long solenoid F = -evB sin180° = 0 (θ = 0°) as magnetic field and velocity are parallel. The electron will continue to move with uniform velocity along the axis of the solenoid.
Question
In a Young's double-slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case,
(a) there shall be alternate interference patterns of red and blue
(b) there shall be an interference pattern for red distinct from that for blue
(c) there shall be no interference fringes
(d) there shall be an interference pattern for red mixing with one for blue
Sol. (c)
For the interference pattern to be formed on the screen, the sources should be coherent and emits lights of same frequency and wavelength.
In a Young's double-slit experiment, when one of the holes is covered by a red filter and another by a blue filter. In this case due to Alteration only red and blue lights are present. In YDSE monochromatic light is used for the formation of fringes on the screen. Hence, in this case there shall be no interference fringes.