Use the Inverse square law, Intensity (I)<span> of a light </span>is inversely proportional to the square of the distance(d).
I=1/(d*d)
Let Intensity for lamp 1 is L1 distance be D1 so on, L2 D2 for Intensity for lamp 2 and its distance.
L1/L2=(D2*D2)/(D1*D1)
L1/15=(200*200)/(400*400)
L1=15*0.25
L1=3.75 <span>candela</span>
Explanation:
It is given that,
Mass of the truck, m = 2000 kg
Initial velocity of the truck, u = 34 km/h = 9.44 m/s
Final velocity of the truck, v = 58 km/h = 16.11 m/s
(a) Change in truck's kinetic energy, 



(b) Change in momentum of the truck, 


Hence, this is the required solution.
The equation of the car is given by the equation,
x(t) = 2.31 + 4.90t² - 0.10t⁶
If we are going to differentiate the equation in terms of x, we get the value for velocity.
dx/dt = 9.8t - 0.6t⁵
Calculate for the value of t when dx/dt = 0.
dx/dt = 0 = (9.8 - 0.6t⁴)(t)
The values of t from the equation is approximately equal to 0 and 2.
If we substitute these values to the equation for displacement,
(0) , x = 2.31 + 4.90(0²) - 0.1(0⁶) = 2.31
(2) , x = 2.31 + 4.90(2²) - 0.1(2⁶) = 15.51
Thus, the positions at the instants where velocity is zero are 2.31 and 15.51 meters.
When a current flows through coil, magnetic field is produced around the coil which induces emf also known as back emf. When current in the coil is increased, more magnetic field is produced which in turn increases the induced emf.