JEE 2008 Answers, Solutions,
Paper I:
Curves C
1 (parabola) & C
2 (circle) touch each other exactly at two points. These points are
. This can be verified by rough sketching looking at the symmetry of the curves.
Inverse trigonometric functions based problem:
This could be solved by systematic procedure or even by putting a value for x (say,
). Ans:
.
Parallelopiped volume:
Co-ordinate geometry question based on two factors of two degrees:
Two straight lines and a circle, when a = b, and c is of sign opposite to that of a.
Limit and derivative based question: The key point here was to look for the existence of limit after using LH rule.
Ans: n = 2, m = 2
Power comparison question in three resistor networks:
P1 = 9W, P2 = 18 W, P3 = 4.5 W
Ans: P2 > P1 > P3
The
wrong statement in the context of X-rays generated from X-ray tube:
Cut-off wavelength of the continuous X-rays depends on the atomic number of the target.
Minimum deviation based question involving a non-thin prism using two colours:
Here, the key idea is the symmetrical passage for min. deviation.
In this case, r=A/2 = 30 deg. for both the colours
Gravitation based question:
The answer in which V is an increasing function upto R and then decreasing function is the correct answer.
Write-up based question on collision:
Speed of block at B immediately after collision:
m/s
Speed of block at C just before another collision:
m/s
Vertical component of the velocity at B immediately after collision assuming it to be elastic:
m/s
Hyperconjugation:
Note:
hyperconjugation is also possible but there was no option for that.
Question based on first order and zero order chemical kinetics:
Ans: 0.5 units
Question based on weak monobasic base and HCl (buffer):
Ans: 3.16 x 10
-2 M
Organic Chemistry Write-Up:
I: The only option with triple bond
J,K: The option with triple bond and SOCl
2L: The option with cis double bond characte
