Engineering MCQ's.🎓

Light :  light is defined as radiant energy from a hot body which produces the visual sensation upon human eye.  Luminous flux (Φ) :  It s defined as the total quantity of light energy emmited (radiated) per second from a luminous body like a lamp. Colour vision :  The   sensation of the color is due to the difference in the wave length of the light radiations. The visible light can have wave length between 4000 A° and 7500 A°. Luminous intensity (I) :  The luminous intensity in the direction of the cone is the ratio of flux to the solid angle or it may be defined as the flux emitted by the source per unit solid angle.  Its unit is candela or lumens per steradian . Lumen :  It is defined as the amount of luminous flux given out in a space represented by one unit of 'solid angle' by a source having an intensity of one candle power in all directions.  Lumen is unit of luminous flux. Candle power :  candle power of source is defined as the number of lumens emitted by that sourc

            Basic concepts related to AC circuit :- Reactance : -      Reactance is defined as the opposition produced in ac circuit by reactive element auch as capacitor or inductor. It is mejores by ' X ' and its unit is ' ohm '. The reactance is devided into two parts:- Inductive reactance (XL). Capacitive reactance (XC).  Inductive reactance (XL) :-          Inductive reactance is defined as opposition produced in ac circuit by inductor.                       XL = 2πFL Its unit is ohm 2. Capacitive reactance (XC) :-          Capacitive reactance is defined as opposition produced in ac circuit by capacitor.                     XC  = 1/2πFC It's unit is also ' ohm '. Impedance :-      Impedance is defined as opposition produced by combination of resistance and reactance in ac circuit. It's unit is ' ohm '                     Z  = √ R^2 + X^2 Types of power :- Real or true or active power (P). Reactive or imaginary power (Q). Appearent power (