RankLab
Back to Questions
MathsHardMCQ2020 · 09 Jan Shift 2

Q56.In the expansion of ( cosx θ + x sin1 θ )16, if l1 is the least value of the term independent of 8 ≤θ ≤π4 and l2 is the least value of the term independent of x when 16π ≤θ ≤π8 , then the ratio l2 : l1 is equal to: (1) 1 : 8 (2) 16 : 1 (3) 8 : 1 (4) 1 : 16

What This Question Tests

This question combines the binomial theorem to find the term independent of x with trigonometric minimization techniques, requiring careful calculation and range analysis.

Concepts Tested

General term in binomial expansionFinding coefficient of x^0Minimization of trigonometric functions

Formulas Used

T_(r+1) = nCr * (a)^(n-r) * (b)^r

sin(2θ) = 2sinθcosθ

📚 NCERT Sections This Tests

9.17(A) Sin I¢C = 1.44/1.68 Which Gives I¢C = 59°. Total Internal Reflection

Physics Class 12 · Chapter 9

69% match

9.17 (a) sin i¢c = 1.44/1.68 which gives i¢c = 59°. Total internal reflection takes place when i > 59° or when r < rmax = 31°. Now, (sin i /sin r max max ) = 1.68 , which gives imax ~ 60°. Thus, all incident rays of angles in the range 0 < i < 60° will suffer total internal reflections in the pipe. (If the length of the pipe is finite, which it is in practice, there will be a lower limit on i determined by the ratio of the diameter to the length of the pipe.) (b) If there is no outer coating, i¢c = sin–1(1/1.68) = 36.5°. Now, i = 90° will have r = 36.5° and i¢ = 53.5° which is greater than i¢c. Thus, all incident rays (in the range 53.5° < i < 90°) will suffer total internal reflections.

2.1Two Charges 5 × 10–8 C And –3 × 10–8 C Are Located 16 Cm Apart. At

Physics Class 11 · Chapter 2

69% match

2.1 Two charges 5 × 10–8 C and –3 × 10–8 C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.

3.16The Rate Constant For A First Order Reaction Is 60 S–1. How Much Time Will

Chemistry Class 11 · Chapter 3

69% match

3.16 The rate constant for a first order reaction is 60 s–1. How much time will it take to reduce the initial concentration of the reactant to its 1/16th value?