Q – 4.1. For the reaction R ⟶ P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds. Q – 4.2. In a reaction, 2 A ⟶ Products, the concentration of A decrases from […]

Q.1. A small candle 2.5 cm in size is placed 27 cm in front of a concave mirror of radius of curvature 36 cm. At what distance form the mirror should a screen be placed in order of receive a sharp image ? Describe the nature and size of the image. If the candle is […]

Note: If two matrices have different orders then we can neither add nor subtract the matrices but we can multiply the matrices either the orders are same or number of columns of first matrix is equal to the number of rows of second matrix. By definition of equality of matrix as the given matrices are […]

NCERT Solutions for Class 12 Maths and Chapter Wise Solutions, NCERT 12 Maths Relations and Functions Chapter 1 – Exercise. Relations and Functions Q 1. Determine whether each of the following relations are reflexive, symmetric and transitive: Relation R in the set A = {1,2,3, ….., 13, 14} defined as R = {(x, y): 3x-y=0} […]

Q 1. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because – Bacteria are resistant to the toxin Toxin is immature Toxin is inactive Bacteria encloses toxin in a special sac. Ans 1. Toxin is inactive. Q 2. What are transgenic bacteria? Illustrate using any one example. Ans 2. […]

Q.1. A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field  at the centre of the coil? Q.2.A long straight wire carries a current of 35 A. What is the magnitude of the field at a point […]

Q 1. Can you list 10 recombinants which are used in medical practice? Find where they are used as therapeutics (use internet). Ans 1. Some of the important recombinant proteins and their therapeutic uses are listed below: Recombinant proteins Therapeutic uses 1.     Insulin 2.     DNase I 3.     Tissue Plasminogen activator (t-PA) 4.     Anti-thrombin III 5.     […]

Q.1. Which of the following frequency/frequencies will be suitable for beyond the horizon communication using sky waves ? (a) 10 kHz (b) 10 MHz (c) 1 GHz (d) 1000 GHz Sol. Choice (b) is correct. This is because 10 kHz cannot be radiated due to large antenna size. 1 GHz and 1000 GHz will penetrate. […]

Q.1. shows a capacitor made of two circular plates each of radius 12 cm and separated by 5.0 mm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A. (a) Calculate the capacitance and the rate of change of potential difference […]

Q.1.(a) Two stable isotopes of 3Li6 and 3Li7 have respective abundances of 7.5  and 92.5 . These isotopes have masses 6.01512 u and 7.01600 u respectively. Find the atomic weight of lithium.(b) Boron has two stable isotopes 5B10. Their respective masses are 10.01294 u and 11.00931 u, and the atomic weight of boron is 10.811 […]

Sol. (i) In the given matrix, the number of rows is 3 and the number of columns is 4. Therefore, the order of the matrix is 3 × 4. (ii) Since, the order of the matrix is 3 × 4, so there are 3 × 4 = 12 elements in it. 2. If the matrix […]

Biology 12 Organism and Populations Chapter 13 – Exercise, Q 1. How is diapause different from hibernation? Ans 1. Hibernation is the phenomenon commonly depicted by ecothermal (cold-blooded) animals which escape cold by hiding them in shelters such as caves, burrows, cervices, hollow thee trunks, mud etc. revealing minimum physiological activity. This phenomenon is also […]

CHEMISTRY (CHAPTAR 2) NCERT EXERCISES WITH ANSWERS EX 2.1 Q – 2.1 Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCI4) is 22 g of benzene is dissolved in 122 g of carbon tetrachloride. Ans. Mass of solution = Mass of benzene + Mass of carbon tetrachloride = 22 g + 122g = […]

Q – 4.1. From the rate expressions for the following reactions, determine their order of reaction and the dimensions of the rate constants: 3 NO (g) ⟶ N2O (g) + NO2 (g) ; Rate = k [NO]2 H2O2 (aq) + 3 I- (aq) + H+ ⟶ 2 H2O (I) + I-3 ; Rate = k […]

Q.6.1. Suggest a condition under which magnesium could reduce alumina. Ans. The two redox reactions are : Q.6.2. Although thermodynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of aluminium. Why? Ans. Below the temperature (1623 K), corresponding to the point of intersection of Al2 O3 and […]

Q 1. Show that the function f : R* → R* defined by f(x) = 1/x is one-one, where R* is the set of all non-zero real numbers. Is the result true, if the domain R* is replaced by N with co-domain being same as R*? Sol. It is given that f : R* → R* is defined by f(x) = […]

Q.1. In n- type which of the following statement is true: (a) Electrons are majority carriers and trivalent atoms are the dopants (b) Electrons are minority carriers and pentavalent atoms are the dopants (c) Holes are minority carriers and pentavalent atoms are the dopants (d) Holes are majority carries and trivalent atoms are the dopants […]

Q 1. Fill in the blanks: Plants are called as ______ because they fix carbon dioxide. In an ecosystem dominated by trees, the pyramid (of numbers) is ______ type. In aquatic ecosystems, the limiting factor for the productivity is ______. Common detritivores in our ecosystem are ______. The major reservoir of carbon on earth is […]

Q.1. Choose the current alternative from the clues given at the end of each statement : (a) The size of the atom in Thomson’s model is ……. The atomic size in Rutherford’s modal (much greater than/no different from/much less than) (b) IN the ground state of………., electrons are in stable equilibrium, while in …….. electrons […]

Q.1. The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0. 4 Ώ, What is the maximum current that can be drawn from the battery ? Q.2. A battery of emf 10 V and internal resistance 3 Ώ is connected to a resistor. If […]