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# Category Archives: IIT JEE

## What Extra Books shall I buy to excel in Class 12 Physics?

What Extra Books shall I buy to excel in Class 12 Physics?

First of all you should possess the NCERT Text Books. This is a must for Indian Students (Especially for those doing the CBSE syllabus and those who are into Indian Civil Services Exam)

Other than that, the following books are recommended for excellence in Board Examination as well as Various Entrance Exams.

## JEE 2014 IS NEAR … How to do the last minute preparation?

The Engineering aspirants of India are now towards the last round of preparation JEE 2014. The paper pen phase of the 2014 edition of the JEE-Mains is scheduled for April 6 and the online examinations will be conducted on April 9, 11, 12 and 19.

The duration of the examination is three hours and will test the candidates on physics, chemistry and mathematics.

Here we will have a brief discussion on how to go for the last round of preparation in Physics. The visitors are welcomed for participating in the discussion through the comment system. Just post your questions and queries as comments to this post.

In Physics the most important topic is MECHANICS, which includes kinematics, laws of motion, work power energy, rotational motion. Electrostatics, Current electricity, magnetic effects of current, electromagnetic induction and alternating current circuits along with the entire OPTICS are to be taken seriously. If you can make a complete thorough revision during the week ahead, you can certainly score very good marks in Physics.

After that if you get time, revise Bernoulli’s principle, Surface Tension, Elasticity with special attention to Young’s modulus.

These are the portions which need to be understood and applied rather than memorizing.

PLEASE MAKE IT A POINT TO SOLVE ALL THE EXERCISES FROM THE NCERT TEXT BOOK. (Including the additional exercises)

Do not neglect the chapter UNITS AND DIMENSIONS, THE ERROR ANALYSIS ETC.

Practice well, solve maximum number of problems and success will be yours. Have some doubts in Physics? Feel free to discuss them here. The questions can be posted here for discussion and hope to get a suitable answer.

## Refraction through a prism

For an equilateral prism , find two angle of incidence differing by 20 degrees showing same deviation of 40 degrees?

Use the formula $\delta&space;=i_{1}+i_{2}-A$

Here A = 60 degree (Since equilateral prism)

deviation is 40 degree

This gives $A+\delta&space;=i_{1}+i_{2}=100$

Therefore,

the values of angles of incidence are 60 degree and 40 degree

## Force – Impulse – Momentum

Hi All! I’m having mega problems with one part of a physics assignment. Looking for any help.
The details are as follows:

The diagram shows the normal force on Christine’s feet vs. time, as recorded by a force plate while she stands still initially (until point B), then jumps off the plate. (This trial is separate from the one in the previous problem. The graph is over-simplified and idealised, compared to reality.) When her feet leave the plate, the normal force is zero.

1)What is the magnitude of the (upward) impulse generated by the normal force of Christine during the time interval of her jump off the plate?

2)What is the magnitude of the downward impulse due to gravity during this interval?

3)What is the net impulse which propels her upwards when she jumps off the plate? (Recall, the net force on her is the normal force minus the force of gravity.)

4)What is her change in speed upwards for this process?

The graph has NORMAL FORCE (N) on the y-axis and TIME (s) on the X axis.
The line is at a constant 550 N until point B (1.75 seconds) at which time it shoot up vertically to 1550 N at a time of 1.95 seconds. It peaks at this time and position then drops down to 0 N at 2.15 seconds.

Thanks in advance for any guidance that can be provided!

Sara

## Time Dilation problem – Special Relativity

With what speed will a clock have to be moving in order to run at a rate that is one half the rate of a clock at rest?

Posted by Mona

Using the formula for Relativistic Time (according to Special Theory of Relativity)

$T=\frac{T_{0}}{\sqrt{1-\frac{v^{2}}{c^{2}}}}$

√[1 – (v²/c²)] = ½ → v² = (3/4)c²

v = [√3/2]*c = .866c

## Question from Special Relativity

A spacecraft starts from earth moving at constant speed to planet A which is 20 light-hour away from Earth.

It takes 25 hour (according to an earth observer) for a spacecraft to reach this planet. Assuming that clocks are synchronized at the beginning of the journey, compare the time elapsed in the spacecraft frame for this one-way journey with the time elapsed as measured by an earth-based clock?

Posted by Mona

## JEE 2013 emerges in its final form

The Joint Advanced Board (JAB) has announced that the Advanced JEE, scheduled to be conducted on June 2, 2013, will not be subjective and will retain IIT JEE 2012 format. The test will be conducted in two sessions on the same day – each with objective-type multiple choice questions (MCQs). The difficulty level and marks allotted to Advanced JEE exam will also be similar to previous JEEs.

IIT aspirants get another chance at Boards
HRD ministry has allowed IIT aspirants a chance to appear for board exams again next year and improve their board marks. Hence, these students will get a chance to appear for JEE once again. The Central Board of Secondary Education (CBSE) and the state boards would make special arrangements to implement the decision.

Only 10% IITians are girls
Analyzing patterns of the Joint Entrance Examination (JEE) results 2012, the Joint Admission Board found that out of all the students admitted to 15 IITs, only 10% were girls. In other engineering institutes, including prestigious ones, the gender ratio is more balanced as 30-40 per cent girls got accepted.