Answer:
Minimum number of photons required is 1.35 x 10⁵
Explanation:
Given:
Wavelength of the light, λ = 850 nm = 850 x 10⁻⁹ m
Energy of one photon is given by the relation :
 ....(1)
    ....(1)
Here h is Planck's constant and c is speed of light.
Let N be the minimum number of photons needed for triggering receptor.
Minimum energy required for triggering receptor, E₁ = 3.15 x 10⁻¹⁴ J
According to the problem, energy of N number of photons is equal to the energy required for triggering, that is,
E₁ = N x E
Put equation (1) in the above equation.

Substitute 3.15 x 10⁻¹⁴ J for E₁, 850 x 10⁻⁹ m for λ, 6.6 x 10⁻³⁴ J s for h and 3 x 10⁸ m/s for c in the above equation.

N = 1.35 x 10⁵
 
        
             
        
        
        
An example of a negative incentive for producers is the
sharp increase in production costs. Producers are the one who manage the production
costs and even the production budget. Anything that relates the production
department is entitled to the management of production producers.
There is what we called positive and negative incentives and
both of these can affect consumers and producers. Positive incentives are those
situations which will give a certain outcome that will benefit the producers,
for example, during the peak season there will be a high demand of products, and
this gives the chance of producers to demand a higher price from the consumers,
in this situation, there will be a big chance of increase sales.  A sharp increase in production costs is a
loss for the producers.  If there will be
an increase in production costs, the budget will be greatly affective and even
though it is not a peak season, there’s a big chance also to increase prices
which we know, consumers are not fond of.
 
        
             
        
        
        
Answer: buzzer.
The working principle of a buzzer is the conversion of electrical energy to sound energy.
The switch just cuts or permits the flow of current, the motor convertes electrical or other kind of energy into mechanical energy, a bulb converts electrical energy into light and a battery converts chemical energy into electrical energy.
        
                    
             
        
        
        
Answer:
a) 1504.8 J
b) 991.76 J
c) 0J
d) 0J
Explanation:
(a) The work done by the force P on the box is given by the following formula:

P: applied force = 171N
x: distance in which the for P is applied = 8.80m
you replace the values of P and x and obtain:

(b) The work don by the friction force is:

μ = coefficient of kinetic friction = 0.250
M: mass of the box = 46.0kg
g: gravitational constant = 9.8 m/s^2

(c) The Normal force is

but this force does not do work on the box because the direction is perpendicular to the direction of the force P.

(d) the same as before:
