Physics, Chemistry, Mathematics Forums

          \( \sum_{{r}={1}}^{n}[1/(r+1)(r+2)(r+3).....(r+k)\) is equal to

Why vinylic and aromatic halides are inert to both S_N1 and S_N2 reaction mechanisms under normal reaction conditions?

On increasing temperature, why rate of formation of E2 product increases more than that of SN2 product?

If the peak value of current through inductor(L), capacitor(C), resistor(R) in parallel A.C. circuit are 2 mA, 3 mA, 5 mA resp. Then find the peak value of current delivered by the source in the same circuit? 

 If a liquid rises to the same height in two capillaries  of the same material at the same temperature

(A) the hydrostatic pressure at the base of capillaries must be zero

(B) the radius of meniscus must be zero

(C) the weight of the liquid in both capillaries must be equal

(D) the capillaries must be cylindrical and vertical

A small sphere of mass m is dropped from a great height. After it has fallen 100m ,it has attained its terminal velocity and continues to fall at that   speed.The work done by air friction against sphere during the first 100m of fall is:

(A) greater than the work done by air friction in the second 100m

(B) less than the work done by air friction in the second 100m

(C) equal to 100 mg

(D) greater than 100 mg

the sum of p terms of an A.P is q ,and the sum of q terms is p;find the sum of (p+q) terms.

If (2+\( \sqrt{3} \))ⁿ=I+f where I and n are +ve integers and 0<f<1,show that I is an odd integer and (I-f)(1-f)=1

In presence of Ca(OH)₂,CH₃CHO condenses with HCO such that all the alpha-H atoms of CH₃CHO are involved  to form A.A reacts with conc.NaOH to form B and C.B is also obtained when A reacts with HCHO and conc.NaOH solution.Identify A,B and C and explain the reactions.

A heavy but uniform rope of length L is suspended from a ceiling.If the rope is given a sideways jerk at the bottom,how long will it take for the pulse to reach the ceiling?A particle is dropped from the ceiling at the instant the bottom end is given the jerk.Where will the particle meet the pulse?