(Astronomy)

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. UV radiation is called ultraviolet

BabaBlast [244]

Answer: smaller

Ultraviolet radiation has broad range of wavelengths, higher number means greater risk of exposure to UV rays that can be dangerous to skin cells. Sunlight is the main source of electromagnetic radiation and it is transmitted in different wavelengths known as electromagnetic spectrum. This spectrum is divided into several regions in order of decreasing wavelength and increasing energy and frequency. UV radiation has frequency and energy that is higher than purple light or violet radiation and the wavelength of ultraviolet radiation is smaller than violet radiation.

8 0

3 years ago

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What is an example of a wave that is not mechanical and how is it different?

vovikov84 [41]

Answer:

light is an example of a wave that is not mechanical .

it is different as it does not need material medium for its propagation

5 0

3 years ago

A 2 kg toy car moves at a speed of 5 m/s.<br> What is the kinetic energy of the car?

ANTONII [103]

Answer:

<h2>The answer is 25 J</h2>

Explanation:

The kinetic energy of an object can be found by using the formula

$KE = \frac{1}{2} m {v}^{2} \\$

m is the mass

v is the velocity

From the question we have

$KE = \frac{1}{2} \times 2 \times {5}^{2} \\ = 1 \times {5}^{2}$

We have the final answer as

Hope this helps you

5 0

2 years ago

The time, t, required to drive a fixed distance varies inversely as the speed, r. It takes 3 hr at a speed of 14 km/h to driv

kenny6666 [7]

Answer:

time taken with speed 23 km/h will be 1.8 hours or 1 hour 48 minutes

Explanation:

Given:

Time is inversely proportional to the speed

mathematically,

t ∝ (1/r)

let the proportionality constant be 'k'

thus,

t = k/r

therefore, for case 1

time = 3 hr

speed = 14 km/hr

3 = k/14

also,

for case 2

let the time be = t

r = 23 km/h

thus,

we have

t = k/23

on dividing equation 2 by 1

we get

$\frac{t}{3}=\frac{k/23}{k/14}$

or

$t=\frac{14\times3}{23}$

or

t = 1.8 hr = or 1 hour 48 minutes ( 0.8 hours × 60 minutes/hour = 48 minutes)

4 0

2 years ago

Consider steady-state conditions for one-dimensional conduction in a plane wall having a thermal conductivity k = 50 W/m · K and

tatuchka [14]

Answer:

solution:

dT/dx =T2-T1/L

&

q_x = -k*(dT/dx)

dT/dx= (-20-50)/0.35==> -280 K/m

q_x =-50*(-280)*10^3==>14 kW

Case (2)

dT/dx= (-10+30)/0.35==> 80 K/m

q_x =-50*(80)*10^3==>-4 kW

Case (2)

dT/dx= (-10+30)/0.35==> 80 K/m

q_x =-50*(80)*10^3==>-4 kW

Case (3)

q_x =-50*(160)*10^3==>-8 kW

T2=T1+dT/dx*L=70+160*0.25==> 110° C

Case (4)

q_x =-50*(-80)*10^3==>4 kW

T1=T2-dT/dx*L=40+80*0.25==> 60° C

Case (5)

q_x =-50*(200)*10^3==>-10 kW

T1=T2-dT/dx*L=30-200*0.25==> -20° C

note:

all graph are attached

6 0

3 years ago