Choose the correct option. Justify your choice. (1 + tan θ + sec θ) (1 + cot θ – cosec θ) =?. (A) 0 (B) 1 (C) 2 (D) – 1
Answer: (C) 2 (1 + tan θ + sec θ) (1 + cot θ – cosec θ) We know that,... View Article
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Choose the correct option. Justify your choice. (sec A + tan A) (1 – sin A) =? (A) sec A (B) sin A (C) cosec A (D) cos A
Answer: (D) cos A We know that, sec A= 1/cos A tan A = sin A / cos A Now,... View Article
Choose the correct option. Justify your choice. 1 + tan2A/1 + cot2A =? (A) sec2 A (B) -1 (C) cot2A (D) tan2A
Answer: (D) tan2A We know that, tan2A =1/cot2A Now, substitute this in the given equation, we get 1 + tan2A/1... View Article
Choose the correct option. Justify your choice. 9 sec2A – 9 tan2A =? (A) 1 (B) 9 (C) 8 (D) 0
Answer: (B) 9 9 sec2A – 9 tan2A Take 9 outside, and it becomes = 9 (sec2A – tan2A) ∵... View Article
Classify the changes involved in the following processes as physical or chemical changes: (a) Photosynthesis (b) Dissolving sugar in water (c) Burning of coal (d) Melting of wax (e) Beating aluminium to make aluminium foil (f ) Digestion of food
Answer: Physical change – A substance is said to undergo a physical change when only the physical properties such as... View Article
Classify the following as linear, quadratic and cubic polynomials: 1 + x
Answer: Linear polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: 3t
Answer: Linear polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: 7x3
Answer: Cubic polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: r2
Answer: Quadratic polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: x – x3
Answer: Cubic polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: x2 + x
Answer: Quadratic polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following as linear, quadratic and cubic polynomials: y + y2 + 4
Answer: Quadratic polynomial A polynomial is an algebraic expression in which the exponent on any variable is a whole number.... View Article
Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories? x + y, 1000, x + x2 + x3 + x4 , 7 + y + 5x, 2y – 3y2 , 2y – 3y2 + 4y3 , 5x – 4y + 3xy, 4z – 15z2 , ab + bc + cd + da, pqr, p2q + pq2 , 2p + 2q.
Answer: Polynomials are algebraic expressions that consist of variables and coefficients. Polynomials are of 3 different types and are classified... View Article
Cleaning of water is a process of removing ____________.
Answer: Cleaning of water is a process of removing pollutants. The process of removing pollutants from water before it enters... View Article
Consider the list of terms given below (i) Tsunami (ii) Landslide (iii) Floods (iv) Lightning Earthquakes can cause (a) (i), (ii) & (iii) (b) (ii) & (iv) (c) (ii), (iii) & (iv) (d) (iii) & (iv)
Answer: (a) (i), (ii) & (iii) An earthquake is a sudden shaking or trembling of the earth caused by the... View Article
Consider the list of terms given below: (i) Seismic Zone (ii) Fault Zone (iii) Mantle (iv) Inner Core The boundaries of the earth’s plate are known as (a) (i) & (ii) (b) (i) & (iii) (c) (iii) & (iv) (d) (ii), (iii) & (iv)
Answer: (a) (i) & (ii) An earthquake is a quick trembling or shaking of the earth that lasts only for... View Article
Describe an activity to show that thermoplastic is a poor conductor of electricity
Answer: All the plastic materials can be softened and melted by heating, but they set again when cool is called... View Article
Describe how crystals of copper sulphate are prepared.
Answer: Crystals of copper sulphate are prepared using the crystallization method, which is described as follows Take a cupful of... View Article
Describe the process of neutralisation with the help of an example.
Answer: An acid-base reaction in which an acid combines with a base to produce salt and water is known as... View Article
Describe with the help of a diagram an instrument which can be used to detect a charged body.
Answer: An electroscope is a scientific device that is used to detect the presence of an electric charge on a... View Article
