NCERT 2022 | How to calculate Log and Antilogs using Table in 10 Minutes | Maths Basics|By Arun Sir

In a nuclear reactor, the neutrons produced in fission reaction have high kinetic energy of the order of few MeV. Whereas the U^(235) nucleus fissions only iwht a slow neutron. In a reactor heavy water (D_(2)O) is used to slow down the neutrons. A neutron hiting a deuterium nucleus slows down quickly. Calculate now many head on, elastic collisions must a neutron have with deuterium nuclei to reduce does not lose energy by any other way apart from collisions with deuterium. [Take "log"_(10)2=0.301 and "log"_(10)3=0.477 ]

Two blocks of mass m_(1)=10kg and m_(2)=5kg connected to each other by a massless inextensible string of length 0.3m are placed along a diameter of the turntable. The coefficient of friction between the table and m_(1) is 0.5 while there is no friction between m_(2) and the table. the table is rotating with an angular velocity of 10rad//s . about a vertical axis passing through its center O . the masses are placed along the diameter of the table on either side of the center O such that the mass m_(1) is at a distance of 0.124m from O . the masses are observed to be at a rest with respect to an observed on the tuntable (g=9.8m//s^(2)) . (a) Calculate the friction on m_(1) (b) What should be the minimum angular speed of the turntable so that the masses will slip from this position? (c ) How should the masses be placed with the string remaining taut so that there is no friction on m_(1) .

An electric pump is used to pump water to fill a water tank of volume 30m^(3) in 20 minute. The pump is on the ground floor and the tank is one the terrace of the building. The centre of the tank is at 400 m above the ground. How much electric power is consumed by the pump, in filling the tank, if the efficiency of the pump is 50%? (g=10m//s^(2) and density of water =10^(3)kg//m^(3) )

For the first order reaction A to 2 B ,1 mole of reactant A gives 0.2 moles of B after 100 minutes. The half life of the reaction is ...... min. (Round off to the nearest integer). [Use ln 2 =0. 69, ln 10 = 2. 3 Properties of logarithms : ln x ^(y) = y ln x, ln ((x)/(y)) = ln x - ln y] Round off to the nearest integer)

Calculating time requireed to complete a definite fraction of first order reaction : A first order reaction is 20% complete in 10 minutes. Calculate the time taken for the reaction to go to 75% completion. Stratagy : First calculate the rate constant (k) using frist data and then calculate the required time to complete 75% of the reaction by using the value of rate constant :

From the following graph of log x//m us log P, calculate mass of H_(@) gas adsorped on the surface of 1gm palladium at pressure of 81 xx 10^(-4)atm . [Express answer in gm) (x)(M) = Mass of gas absorbed per unit mass of absorbent. P = Partial pressure of gas in atm.

There is a circular path around a sports field. Priya takes 12 minutes to drive one round of the field. While Ravish takes 10 minutes for the same. Suppose they both start from the same point and at the same time and go in the same direction. (i) After how many minutes will they meet again at the starting point ? (ii) Which mathematical concept is used in this problem ? (iii) What is the value discussed in this problem ?