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3 years ago

A 3.6-volt battery is used to operate a cell phone

2 answers:

4 0

The equation with the values for this one is P = VI, and we know some of the values, so substituting them in:

0.064 = 3.6 x I
I=0.064/3.6
=0.0177 = 0.018A

Marina CMI [18]3 years ago

3 0

Explanation :

It is given that,

Potential energy, $V=3.6\ V$

Power dissipated, $P=0.064\ Watt$

We know that the power dissipated is given by :

$P=VI$

I is the current passing through the phone.

$I=\dfrac{P}{V}$

$I=\dfrac{0.064\ W}{3.6\ V}$

$I=0.017\ A$

I = 0.018 A

Hence, the current that passes through the phone is (1) 0.018 A.

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What is meant by a colored shadow? If "shadow" means

Natasha_Volkova [10]

Explanation:

Red, green, and blue are therefore called additive primaries of light. ... When you block two lights, you see a shadow of the third color—for example, block the red and green lights and you get a blue shadow. If you block only one of the lights, you get a shadow whose color is a mixture of the other two.

First, your definition of a shadow is incorrect. A shadow is an area that receives less light than its surroundings because a specific source of light is blocked by whatever is "casting" the shadow. Your example of being outside reveals this. The sky and everything around you in the environment (unless you are surrounded by pitch black buildings) is sending more than enough light into your shadow, to reveal the pen to your eyes. The sky itself diffuses the sunlight everywhere, and the clouds reflect plenty of light when they are not directly in front of the Sun.

If you are indoors and have two light bulbs, you can throw two shadows at the same time, possibly of different darknesses, depending on the brightness of the light bulbs.

It can take a lot of work to get a room pitch black. One little hole or crack in some heavy window curtains can be enough to illuminate the room. There are very few perfectly dark shadows.

4 0

3 years ago

A motorcycle is following a car that is traveling at constant speed on a straight highway. Initially, the car and the motorcycle

n200080 [17]

Answer:

a) 4.9 s

b) 167.8 m

Explanation:

Hello!

To solve this question we need to make use of the equations of motion of both the motorcycle xm(t) and the car xc(t) at t=5

Let us consider the position of the motorcycle at t=5 as the origin, that is:

xm(t+5) = vt + (1/2)at^2

xc(t+5) = vt + 60 m

where v = 22.0m/s and a=5m/s^2

We are looking for the time t' when the position of the car and the motorcycle are the same:

xm(t'+5)=xc(t'+5)

vt' + (1/2)at'^2 = vt' +60m

t' = √(120 m /a) = 4.89898... s

Since we are considering the origin of the cooordinate system at the position when the motorcycle starts to accelerate, the distance travelled by the motorcycle until it catches the car is given by:

xm(t'+5)= vt' + (1/2)at'^2

xm(9.89898s) = (22 * 9.89898 + 2.5 * 9.89898^2)m

xm(9.89898s)= 167.777... m

3 0

3 years ago

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses

Tom [10]

Answer:

a) U = 0.375 mJ

b) p_rad = 4.08 mPa

c) λ_med = 604 nm ; f_med = 3.7 * 10^14 Hz

d) E_o = 3.04 * 10^4 V / m , B _o = 1.013 *10^-4 Nm/Amp

Explanation:

Given:

λ_air : wavelength = 810 * 10^(-9) m

P: Power delivered = 0.25 W

d : Diameter of circular spot = 0.00051 m

c : speed of light vacuum = 3 * 10^8 m/s

n_air : refraction Index of light in air = 1

n_med : refraction Index of light in medium = 1.34

ε_o : permittivity of free space = 8.85 * 10^-12 C / Vm

part a

The Energy delivered to retina per pulse given that laser pulses are 1.50 ms long:

U = P*t

U = (0.25 ) * (0.0015 )

U = 0.375 mJ

Answer : U = 0.375 mJ

part b

What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed?

p_rad = I / c

Where I : Intensity = P / A

p_rad = P / A*c

Where A : Area of circular spot = pi*d^2 / 4

p_rad = 4P / pi*d^2*c

p_rad = 4(0.25) / pi*0.00051^2*(3.0 * 10^8)

p_rad = 0.00408 Pa

Answer : p_rad = 4.08 mPa

part c

What are the wavelength and frequency of the laser light inside the vitreous humor of the eye?

λ_med = n_air*λ_air / n_med

λ_med = (1) * (810 nm) / 1.34

λ_med = 604 nm

f_med = f_air

f_med = c / λ_air

f_med = (3*10^8) / (810 * 10^-9)

f_med = 3.7 * 10^14 Hz

Answer : λ_med = 604 nm ; f_med = 3.7 * 10^14 Hz

What is the electric and magnetic field amplitude in the laser beam?

I = P / A

I = 0.5*ε_o*c*E_o ^2

I = 4P / pi*d^2

Hence, E_o = ( 8 P / ε_o*c*pi*d^2 ) ^ 0.5

E_o = ( 8 * 0.25 / (8.85*10^-12) * (3*10^8) * π * (0.00051)^2) ^ 0.5

E_o = 3.04 * 10^4 V / m

For maximum magnetic field strength:

B_o = E_o / c

B_o = 3.04 * 10^4 / (3*10^8)

B _o = 1.013 *10^-4 Nm/Amp

Answer: E_o = 3.04 * 10^4 V / m , B _o = 1.013 *10^-4 Nm/Amp

5 0

3 years ago

A 10248 kg car is pulled by a low tow truck that has an acceleration of 2.0m/s what is the net force on the car

Ksenya-84 [330]

Answer: 20496N

Explanation:

The formula to calculate the net force will be given as:

Net force = Acceleration × Mass

Since 10248 kg car is pulled by a low tow truck that has an acceleration of 2.0m/s, the net force would be:

= 10248 × 2

= 20496N

8 0

3 years ago

Mice eat insects and get eaten by owls. In which case would a population of mice increase?

creativ13 [48]

The populations of insects increases I believe? Please correct me if I’m wrong

7 0

3 years ago