A fisherman’s scale stretches 3.6 cm when a 2.7-kg fish hangs from it. (a) What is the spring stiffness constant and (b) what will be the amplitude and frequency of vibration if the fish is pulled down 2.5 cm more and released so that it vibrates up and down?

Solution Step 1 List out the variables Power for 1 LED = 1.0 W Efficiency of 1 LED = 20 % or 0.2 Output power of 1 LED, P out Output power required from LED combination = 1.6 W Number of LEDs required, N = Total power required to run LED light source, P (total) = We have to follow this sequence of variable listing in order to reach till end. Step 2 Finding out the output power of 1 LED The efficiency, = Energy output / Energy input = Power output / power input So, Power output = Efficiency, X Power input Output power of 1 LED, P out 0.2 X 1 W = 0.2 W.