Which mirror is used by a dentist to focus light on tooth of a patient?
A concave mirror is used by the dentist to focus light on the tooth of a patient because it has... View Article
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Explain why holes are made in hanging banners and hoardings.
Answer: If banners and hoarding do not have holes in them, then due to air pressure banners and hoardings may... View Article
Supercharging is the process of: (A) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere (B) Providing forced cooling air (C) Injecting excess fuel for raising more loads (D) Supplying compressed air to remove combustion products fully
Answer: (A) Supercharging is the process of supplying the intake of an engine with air at a density greater than... View Article
How many electrons are there in one coulomb of electricity?
1 Columb of charge contains 6.25 × 1018 electrons.
Define angle of friction.
The angle between the resultant of frictional force and the normal reaction makes with the normal force is called the... View Article
A passenger in a moving train tosses a coin upward which falls behind him. It implies that the motion of the train is: (A) Uniform (B) Accelerated (C) Along the circular tracks (D) Retarded
Answer: (B) Accelerated A passenger in a moving train tosses a coin upward which falls behind him. It implies that... View Article
What is meant by the Solar System?
Answer: The sun together with eight planets and the other group of celestial bodies forms the Solar system. These planets... View Article
Winds are generated due to heating on the earth. True or False
True. Winds are generated due to uneven heating on the earth by the Sun. The earth absorbs the sun’s radiation... View Article
SI unit of conductance is:
SI unit of conductance is Siemen or ohm-1 or mho. The conductance in siemens is the reciprocal of resistance in... View Article
State and explain amperes circuital law
In electromagnetism, Ampère’s circuital law relates the integrated magnetic field around a closed loop to the electric current passing through... View Article
The magnetic susceptibility is negative forThe magnetic susceptibility is negative for (1) Diamagnetic material only (2) Paramagnetic material (3) Ferromagnetic material (4) Paramagnetic and ferromagnetic material
Answer: (1) Diamagnetic material only In electromagnetism, magnetic susceptibility is defined as the measure of how much a material will be... View Article
The basic unit of speed is?
The basic unit of Speed is meter per second or m/s. The SI unit of distance is meter(m) and time... View Article
Find the LCM of 40, 48 and 45.
By prime factorisation method, we can write the numbers 40, 48 and 45 as: 40 = 2 x 2 x... View Article
Find the multiplicative inverse of the following. (i) -13 (ii) -13/9 (iii) 1/5 (iv) -5/8 x -3/7 (v) -1 x -2/5 (vi) −1
The multiplicative inverse of: (i) -13 is -1/13 (ii) -13/9 is -9/13 (iii) 1/5 is 5 (iv) -5/8 x -3/7... View Article
Factorise the follwing expression p2+6p-16.
Given, p2 + 6p – 16 By splitting the middle term; p2 – 2p + 8p -16 (p2 – 2p)... View Article
Write the following cubes in expanded form: (i) (2x + 1)^3 (ii) (2a – 3b)^3 (iii) [3x/2 + 1]^3 (iv) [x – 2y/3]^3.
(i) (2x + 1)³ Using identity: (a + b)³ = a³+ b³+ 3ab(a + b) (2x + 1)³ = (2x)³... View Article
Find the zeroes of the polynomial x^2+1/6x-2 and verify the relation between the coefficient and zeroes of the polynomial.
x2 + 1/6(x) – 2 = 0 6x2 + x – 12 = 0 6x2 – 8x + 9x –... View Article
Convert the following ratios to percentages? (a) 3:4 (b) 2:3
(a) Given, the ratio is 3:4 3:4 = 3/4 Percentage = 3/4 x 100 = 3 x 25 = 75%... View Article
What is formula of x²+y²?
Since we know, (x+y)2 = x2 + y2 + 2xy Therefore, the formula of x2 + y2 is: x2 +... View Article
Square of 42 without actual multiplication.
Given, the number is 42. We need to square the number 42. We can use the identity: (a+b)2 = a2... View Article
