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Find the degree measure of 1/4 radian.

Solution: We know π radian = 180 degrees. So 1 radian = 180/π 1/4 radian = (180/π)×1/4 = 45/π = 45 ×7/22 =... View Article

The value of sin² 5⁰ + sin² 10⁰ + sin² 15⁰ + … + sin² 85⁰ + sin² 90⁰ is

(A) 7 (B) 8 (C) 9.5 (D) 10 Solution: We know sin (90-x) = cos x sin2(90-x) = cos2 x Also sin2x + cos2 x = 1 sin2 50 +... View Article

Find the points of the intersection of the medians of a triangle whose vertices are (-1, 0), (5, -2) and (8, 2).

Solution: The points of the intersection of the medians of a triangle is the centroid. Let A(-1, 0), B(5, -2) and C(8, 2) be the vertices of... View Article

Find the value of 95 × 95 using the algebraic identity.

Solution: We know (a-b)2 = a2- 2ab + b2 95 = 100-5 95 × 95 = 952 = (100 - 5)2 = 1002 - 1000 + 52 = 10000 - 1000 + 25 = 9025... View Article

Is 2352 a perfect square? If not, find the smallest number by which 2352 must be multiplied so that the product is a perfect square. Find the square root of the new number.

Answer: Square root of 2352 = 48.497 It is not a perfect square. Let us prime factorise 2352. 2352 =... View Article

Fill in the blank with the most suitable determiner. “Would you like ________ coffee?” my host asked.

(A) some (B) any (C) little (D) much Answer: A determiner denotes whether the noun is referring to a definite or indefinite element of a... View Article

Solve the following equation 13x – 5 = 3/2

Solution: 13x - 5 = 3/2 13x = 3/2 + 5 = (3+10)/2 = 13/2 => x = 1/2... View Article

If 1/5: 1/x = 1/x :1/125 then the value of x is

(a) 15 (b) 20 (c) 25 (d) 35 Solution: ⅕: 1/x = 1/x :1/125 Product of extremes = product of means (⅕) ×(1/125) = (1/x) ×... View Article

05 Nov 2021: The Hindu Analysis

There is no Hindu Analysis for today since there is no edition of 'The Hindu' newspaper.... View Article

A step-down transformer reduces the voltage of a transmission line from 2200 V to 220 V. The power delivered by it is 880 W and its efficiency is 88%. The input current is

1) 4.65 mA 2) 0.045 A 3) 0.45 A 4) 4.65 A Answer:3) 0.45 A Solution: η = 88 % = 88/100 η = output power/input power 88/100 =... View Article

A current of 5 A is flowing at 220 V in the primary coil of a transformer. If the voltage produced in the secondary coil is 2200 V and 50% of power is lost, then the current in the secondary will be

1) 2.5 A 2) 5 A 3) 0.25 A 4) 0.5 A Answer: 3) 0.25 A Solution: Output power is half of the input power Ps = 0.5 Pp VsIs = 0.5 VpIp... View Article

A generator at a utility company produces 100 A of current at 4000 V. The voltage is stepped-up to 240000 V by a transformer before it is sent on a high voltage transmission line. The current in the transmission line is

1) 3.67 A 2) 2.67 A 3) 1.67 A 4) 2.40 A Answer: 3) 1.67 A Solution: V1I1 = V2I2 4000 x 100 = 240000 x I2 I2 = (4000 x... View Article

Fleming’s left and right-hand rules are used in

1) DC motor and AC generator 2) DC generator and AC motor 3) DC motor and DC generator 4) Both rules are the same, anyone can be used... View Article

The transformation ratio in the step-up transformer is

1) one 2) greater than one 3) less than one 4) the ratio greater or less than one depends on the other factors Answer: 2) greater than... View Article

A transformer of efficiency 90% draws an input power of 4 kW. An electrical appliance connected across the secondary draws a current of 6 A. The impedance of the device is

1) 60 Ω 2) 50 Ω 3) 80 Ω 4) 100 Ω 5) 120 Ω Answer: 4) 100 Ω Solution: η = 90/100 = 0.9 = output power/input power P0... View Article

An electric motor runs a DC source of emf 200 V and draws a current of 10 A. If the efficiency is 40%, then the resistance of the armature is

1) 5 Ω 2) 12 Ω 3) 120 Ω 4) 160 Ω Answer: 2) 12 Ω Solution: Input power = VI = 200 x 10 = 2000 W Output power = (40/100) x 2000 = 800... View Article

Energy associated with a moving charge is due to

1) electric field 2) magnetic field 3) Both (a) and (b) 4) None of these Answer: 1) electric field Solution: The energy associated... View Article

In a coil when current changes from 10 A to 2 A in time 0.1 s, induced emf is 3.28 V. What is self-inductance of the coil?

1) 4H 2) 0.4 H 3) 0.04 H 4) 5 H Answer: 3) 0.04 H Solution: Induced emf = L x (di/dt) 3.28 V = L x [(10-2)/0.1] = L x 80 ⇒ L =... View Article

If coil is open, then L and R become

1) ∞ and 0 2) 0 and ∞ 3) ∞ and ∞ 4) 0 and 0 Answer: 2) 0 and ∞ Solution: When the coil is open, the... View Article

A solenoid of inductance 2 H carries a current 1 A. What is the magnetic energy stored in a solenoid?

1) 2 J 2) 1 J 3) 4 J 4) 5 J Answer:2) 1 J Solution: Magnetic energy stored, Um = (1/2)Li2 = (1/2) x 2 x 12 = 1 J... View Article