1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
nekit [7.7K]
2 years ago
8

Light of a given wavelength is used to illuminate the surfacce of a metal, however, no photoelectrons are emitted. In order to c

ause electrons to be ejected from the surface of this metal you shouldA. use light of the same wavelength but increase its intensity.B. use light of a shorter wavelength.C. use light of the same wavelength but decrease its intensity.D. use light of a longer wavelength.
Physics
1 answer:
Jlenok [28]2 years ago
6 0

Answer:

B. use light of a shorter wavelength.

Explanation:

We know that

E= \frac{hc}{\lambda}

h= plank's constant

c= speed of light

λ= wavelength of the incident light

so, in order to have sufficient energy for for the emission of electron, the incident's radiation must have λ small enough.

B. use light of a shorter wavelength.

You might be interested in
Which of the following scenarios would be optimal for obtaining a date from radioactive decay using these isotopes: 87Rb, 147Sm,
REY [17]

Answer:

a) 238U, 40K and 87Rb, b)   235U and to a lesser extent 40K , c)  he 235U,

d) possibility is 14C , e)this period would be ideal for 14C , f) 14C should be used since it is the one with the least average life time, even though the measurements must be very careful

Explanation:

One of the applications of radioactive decay is the dating of different systems.

To do this, the quantity of radioactive material in a meter is determined and with the average life time, the time of the sample is found.

Let's write the half-life times of the given materials

87Rb T ½ = 4.75 1010 years

147Sm T ½ = 1.06 1011 years

235U = 7,038 108 years

238U = 4.47 109 years

40K = 1,248 109 years

14C = 5,568 103 years

we already have the half-life of the different elements given

a) meteors. As these decomposed in the formation of the solar system, their life time is around 3 109 to 5 109 years, so it is necessary to look for elements that have a life time of this order, among the candidates we have 238U, 40K and 87Rb if these elements were at the moment of the formation of these meteors, there must still be rations in them, instead elements 14C already completely adequate

b) rock. The formation period is 4.20-108 years, therefore one of the most promising elements is 235U and to a lesser extent 40K since it is more abundant in rocks. The other elements with higher life times have not decayed and therefore will not give a true value and the 14C is completely decayed

c) volcanic ash. Formation time 6107 years, the only element that has the possibility of having a count is the 235U, the others have a life time so long that they have not decayed and the 14C is complete, unbent

d) scarp of an earthquake formation time 5 101 years, The only one that has any possibility is 14C even when it has declined very little, all the others, you have time to long that has not decayed

e) INCA excavation. The time of this civilization is about 10000 to 500 years (104 to 5 102 years), we see that this period would be ideal for 14C since it has some period of cementation, the others have not decayed

f) Tree in Blepharitis. 14C should be used since it is the one with the least average life time, even though the measurements must be very careful because of a period of disintegration. We have such a long time that they have not decayed

8 0
3 years ago
If you were given distance and period of time, what can you calculate?
antiseptic1488 [7]

If you were given distance & period of time, you would be able to calculate the speed.

Hope this helps!

3 0
3 years ago
In your own words describe the motion of convection currents?
Marysya12 [62]
Convection is the circular motion that occurs as hotter air or liquid increases when the cooler air or liquid drops down, and has faster moving molecules, rendering it less dense. Convection currents within the earth shift layers of magma, and currents are formed by convection in the ocean.
5 0
2 years ago
Read 2 more answers
Holden is trying to determine the velocity of his race car. He went 20 meters east, turned around, and went 40 meters west. His
Ludmilka [50]

Answer:

12 m/s west

Explanation:

4 0
3 years ago
Read 2 more answers
Which of the following types of rocks are likely to be formed due to heat and pressure? Sedimentary rock only Metamorphic rock o
KiRa [710]
It is metamorphic rock only
6 0
2 years ago
Read 2 more answers
Other questions:
  • Earth is broken into how may climate zones
    6·1 answer
  • 8) A flat circular loop having one turn and radius 5.0 cm is positioned with its plane perpendicular to a uniform 0.60-T magneti
    12·1 answer
  • A traveler first drives 18.6 km east, then 30.3 km southeast, and finally 10.7 km south. Find the traveler's total displacement
    14·1 answer
  • A bicyclist notes that the pedal sprocket has a radius of rp = 11 cm while the wheel sprocket has a radius of rw = 4.5 cm. The t
    11·1 answer
  • The asteroid 2007 VK184 has one chance in 2940 of hitting the Earth between the years 2048 and 2057. The asteroid is 130 meters
    15·1 answer
  • What is the kinetic energy of a 10-kg bicycle moving at 10 m/s?​
    10·1 answer
  • The energy of a photon is inversely proportional to the wavelength of the radiation. (T/F)
    12·1 answer
  • Plz help me with these :)
    12·2 answers
  • A train travels 2km in 100 seconds. find the velocity of the train
    13·1 answer
  • A fast-moving car has 0.5 MJ of kinetic energy.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!