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The phase difference between current and voltage in an AC circuit is π/4 radian. If the frequency of AC is 50Hz, then the phase difference is equivalent to the time difference?

Solution: The phase difference between current and voltage is given by is equivalent to 0.0025s or t=2.5ms... View Article

A truck and a car moving with the same kinetic energy are brought to rest by the application of brakes which provides equal retarding forces. Which of them will come to rest in a shorter distance?

a) The truck b) The car c) Both will travel the same distance before coming to rest d) Cannot be predicted Solution:c) Both will travel the... View Article

Assertion: A body can have acceleration even if its velocity is zero at a given instant of time. Reason: A body is numerically at rest when it reverses its direction.

a) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion. b) Both Assertion and Reason are correct but... View Article

Energy dissipated in the LCR circuit in :

a) R only b) L only c) C only d) All the above option Solution: a) R only Explanation: In an LCR circuit, the energy is dissipated through... View Article

A flood light is covered with a filter that transmits red light. The electric field of the emerging beam is represented by a sinusoidal plane wave [latex]E_{x}=36 sin (1.2010^{7}z+610^{15}t)[/latex] V/m. What will be the average intensity of the beam?

Solution: Average intensity is given by the formula:... View Article

An rlc circuit is driven by a sinusoidal EMF with angular frequency. If angular frequency is increased without changing the amplitude of the EMF , the current amplitude increases, it means?

a. b. c. d. None of the option Solution: Option (c) Explanation: Given, the current amplitude is increased with the emf amplitude... View Article

A compass needle just above a wire in which electrons are moving towards east, will point:

a. South b. North c. East d. West Solution: a. South A compass needle points towards the magnetic south pole.... View Article

A beam of parallel rays is brought to focus by a plano-convex lens. A thin concave lens of the same focal length is joined to the first lens. The effect of this is:

a. The focal point shifts towards the lens by a small distance. b. The focus shifts to infinity. c. The focus remains undisturbed. d. The... View Article

If a rubber cube is taken 50m deep in a lake its volume reduces by 0.5% the bulk modulus of a rubber is nearly

Solution: =96m... View Article

The ratio of kinetic energy of a planet at perigee and apogee during its motion around the sun in an elliptical orbit of eccentricity e is?

Solution: Consider semi major axis = a e= eccentricity distance of apogee is distance of perigee is... View Article

The value of ∠QSR is

Solution: PQ is parallel to RF. Given ∠PQS = 600 So ∠RSE = 600 (corresponding angles are equal) ∠QSR = 180 -60 = 1200 (linear pair)... View Article

Convert the given statement into expression form and simplify: one-fifth of a number minus 4 gives 3.

Solution: Let x be the number. One-fifth of the number = (⅕)×x = x/5 One-fifth of a number minus 4 gives 3 = (x/5) - 4 = 3 The... View Article

The pairs of natural numbers whose least common multiple is 78 and the greatest common divisor is 13 are:

Solution: Let x and y be the numbers. We know LCM × GCD = product of two numbers => 78×13 = xy => xy = 1014 1014 =... View Article

Convert 5.523333 into fraction.

Solution: To convert a decimal to a fraction, count the number of digits after the decimal point in the given number. Let it be n. Multiply... View Article

If n and r are integers such that 1≤r≤n, then n. C(n-1, r-1) =

(a) C(n, r) (b) r. C(n, r) (c) n. C(n, r) (d) none of these Solution: We know C(n, r) = n!/r!(n-r)! C(n-1, r-1) = (n-1)!/(r-1)! (n-r)!... View Article

If a vector A = 2i + 2j + 3k and B = 3i + 6j + nk are perpendicular to each other, then the value of n is

Solution: If two vectors are perpendicular, then the dot product is zero. A = 2i + 2j + 3k B = 3i + 6j + nk A.B = 0 => 6+12+3n =... View Article

The angles A, B, C of a triangle ABC are in A. P and a : b = 1: √3 . If c = 4 cm, then the area (in sq. cm) of this triangle is

Solution: Given that the angles A, B, C of a triangle ABC are in A. P. => 2B = A+C We know A+B+C = 1800 => 3B = 180 => B = 600... View Article

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