First we must convert each value of energy to Joules by multiplying its value by 1.6 ×10^-19. After that, we can now obtain the wavelength from E= hc/λ

Where;

h= planks constant

c= speed of light

λ= wavelength of light

For 6.0ev;

E= 6.0 × 1.6 ×10^-19

E= 9.6 × 10^-19 J

From

E= hc/λ

λ= hc/E

λ= 6.6 × 10^-34 × 3 × 10^8/9.6 × 10^-19

λ= 2.1 × 10^-7 m

For 4.0 eV

4.0 × 1.6 × 10^-19 = 6.4 × 10^-19 J

E= hc/λ

λ= hc/E

λ= 6.6 × 10^-34 × 3 × 10^8/6.4 × 10^-19

λ= 3.1 × 10^- 7 m

3 0

3 years ago

Is mechanical advantage always greater than one?

oee [108]

No, it can also be less than 1 depending on the class of the lever.

6 0

3 years ago

A 750 Watt hairdryer is used for 15 minutes. Calculate the Kwhr used. Calculate the cost to use 15 min. every day for 1 year @ 8

Rufina [12.5K]

Part (a):
We know that:
1 kw = 1000 watt ..........> Therefore, to convert watt into kw, we will divide by 1000
1 hour = 60 min ..........> Therefore, to convert mins into hours, we will divide by 60
Based on the above, the conversion results for the two units together would be as follows:
1 watt minute is equivalent to <span>0.000017 kilowatt hours
</span>Now, for the given , we will simply use cross multiplication to do the conversion as follows:
1 watt minute..............> 0.000017 kilowatt hours
750*15 ................> ??
750*15 watt min = 0.19125 kilowatt hour

Part (b):
From part a, we have that the consumption is 0.19125 kilowatt hour per day. Assuming that the year is 365 days, we would have:
yearly consumption = 0.19125 * 365 = 69.80625 kilowatt hour
The cost is 8 cents/kilowatt hour
Therefore:
yearly cost = 69.80625 * 8 = 558.45 cents

Hope this helps :)

8 0

2 years ago

Read 2 more answers

A ball at rest rolls across a frictionless floor at 12.0 m/s/s. How far will it travel in

professor190 [17]

Answer:

The distance, d travelled by the ball is 768 metres.

Explanation:

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of final speed from the initial speed all over time.

Hence, if we subtract the final speed from the initial speed and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;