Archives

State whether each of the following statements are true or false. If the statement is false rewrite the given statement correctly (i) If P = {m, n} and Q = {n, m} then P x Q = {(m x n), (n, m)} (ii) If A and B are non-empty sets then A x B is a non-empty set of ordered pairs (x, y) such that x ∈ A and y ∈ B (iii) If A = {1, 2}, B = {3, 4} then A x (B∩ϕ ) = ϕ

(i) Given P = {m,n} and Q = {n, m} then P x Q = {(m, n), (m, m), (n, n), (n, m)} We can observe that the given value of P x Q is incorrect... View Article

A bullet of mass 50 g is moving with a velocity of 500 m/s^-1. It penetrates 10 cm into a still target and comes to rest. Calculate: (a) the kinetic energy possessed by the bullet, and (b) the average retarding force offered by the target

Given Mass of bullet = 50 g = 0.05 kg Velocity = 500 m/s Distance penetrated by the bullet = 10 cm = 0.1 m (a) The kinetic energy of the... View Article

Explain the following statement with reasons. Television is the most popular medium

Television is the most popular medium of communication because of the following reasons: 1. It is an audio-visual medium of communication. 2.... View Article

Electrolytic reduction of alumina to aluminium by Hall-Heroult process is carried out _________ (a) In the presence of NaCl (b) In the presence of fluorite (c) In the presence of cryolite which forms a melt with lower melting temperature (d) In the presence of cryolite which forms a melt with higher melting temperature

The Hall-Heroult process is widely used in the extraction of aluminium. In Hall-Heroults process, pure Al2O3 is mixed with CaF2 or Na3AlF6. This... View Article

What do you mean by linear pair of angles?

Linear pair of angles are formed when two lines intersect each other at a single point. The angles are said to be linear if they are adjacent to... View Article

A prokaryotic autotrophic nitrogen fixing symbiont roots are found in (a) Alnus (b) Cycas (c) Cicer (d) Pisum

A prokaryotic autotrophic nitrogen fixing symbiont roots are found in cycas. Hence, the correct option is (b)... View Article

A family consists of two grandparents two parents and three grandchildren. The average age of the grandparents is 67 years, that of the parents is 35 years and that of the grandchildren is 6 years. What is the average age of the family? (a) 28 (4/7) years (b) 31 (5/7) years (c) 32 (1/7) years (d) None of these

Required average = (67 x 2 + 35 x 2 + 6 x 3)/ (2 + 2 + 3) = (134 + 70 + 18)/7 = 222/7 = 31 (5/7) years Hence, the average age of the family... View Article

Which of the following is not a transmission medium? (a) Telephone lines (b) Coaxial cable (c) Modem (d) Microwave systems (e) Satellite systems

Modem is not a transmission medium. Therefore, the correct option is (c)... View Article

Change the following statement into passive voice. We all know that there is only one God

The passive voice of the given statement is as follows: It is known to us all that there is only one God.... View Article

Appearance of antibiotic resistant bacteria is an example of(a) Adaptive radiation(b) Transduction(c) Pre-existing variation in the population(d) Divergent evolution

The correct answer is (c) pre-existing variation in the population The appearance of antibiotic-resistant bacteria is an example of pre-existing... View Article

A chord of a circle is equal to the radius of the circle. Find the angle subtended by the chord at a point on the minor arc and also at a point on the major arc.

The chord AB is equal to the radius of the circle. OA and OB are the two radii of the circle. From ΔOAB. AB = OA = OB = radius of the... View Article

What effect does branching of an alkane chain has on its boiling point?

Alkanes encounter Van-der Waals forces between molecules. The higher the alkane’s power, the greater is the boiling point. As the molecule... View Article

If Driver = 12, Pedestrian = 20, Accident = 16, then Car = ? (a) 3 (b) 6 (c) 8 (d) 10

Clearly, we can find that each word is coded by the numeral which is twice the number of letters in the word Driver = 6 x 2 = 12 Pedestrian = 10... View Article

How woollen clothes keep us warm in the winter?

Woollen clothes keep us warm in winter because the air will be trapped more in those. We know that air is a bad conductor of heat it does not... View Article

One joule is approximately equal to (a) 0.28 cal (b) 0.32 cal (c) 0.24 cal (d) 4.2 cal

0.24 cal Calorie is the energy in the form of heat required to warm 1 kilogram of water by 10 C 1 calorie = 4.184 joule i.e 4.2 joule or 1... View Article

The pH of boiling water is 6.4. This implies that boiling water is: (a) slightly basic (b) slightly acidic (c) neutral (d) amphoteric

Neutral The pH of boiling water is 6.4. This implies that boiling water is neutral. When water is boiled, both hydrogen ion and hydroxide ion... View Article

Give possible expressions for the length and breadth of the rectangle whose area is given by (i) 25a^2 – 35a + 12 (ii) 24x^2 – 15x

A Rectangle is a four sided-polygon, having all the internal angles equal to 90 degrees. The two sides at each corner or vertex, meet at right... View Article

With reference to black soil answer the following: (i) Name one important crop which grows in this soil (ii) Give one chemical property of this soil

(i) The important crop which grows in the black soil is cotton (ii) Chemically, the black soils are rich in lime, iron, magnesia and alumina.... View Article

Expand the following using identities (3x – 4y)^2

Given (3x - 4y)2 Using Identity (a-b)2 = a2 - 2ab + b2 (3x - 4y)2 = (3x)2 - 2.(3x).(4y) + (4y)2 We get, (3x - 4y)2 = 9x2 - 24xy + 16y2... View Article

In five kingdom system, the main basis of classification: (a) Structure of nucleus (b) Nutrition (c) Structure of cell wall (d) Asexual reproduction

Nutrition Biological Classification of Plants and Animals was first proposed by Aristotle on the basis of simple morphological characters... View Article