The cost of a kilowatt hour of energy in the bill is 0.20 euros. A cylindrical led bulb of 5 W has a luminous flux of 50 lm. What is the luminous efficiency of this light source? Knowing that the bulb is 5cm long, 36mm in diameter, and plugged into a 220V socket, what is the resistivity of the bulb? How much would you spend in a year if you used 5 LED bulbs all on for 12 hours a day?

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.