True or false: All heterotrophs are omnivores.

A small container of water boils at 100°C. The boiling point increases by 1°C for every 12 g of salt dissolved in the water. Det

Slav-nsk [51]

48/12=4 100-4=96 New boiling point is 96

6 0

3 years ago

A light source of wavelength, l, illuminates a metal and ejects photoelectrons with a maximum kinetic energy of 1 eV. A second l

madreJ [45]

Explanation:

From first source, kinetic energy ( $K.E_{1}$ ) ejected is 1 eV and wavelength of light is $\lambda$ .

From second source, kinetic energy ( $K.E_{2}$ ) ejected is 4 eV and wavelength of light is $\frac{\lambda}{2}$ .

Relation between work function, wavelength, and kinetic energy is as follows.

K.E = $\frac{hc}{\lambda} - \phi$

where, h = Plank's constant = $6.63 \times 10^{-34}$ J.s

c = speed of light = $3 \times 10^{8}$ m/s

Also, it is known that 1 eV = $1.6 \times 10^{-19}$ J

Therefore, substituting the values in the above formula as follows.

From first source,

$K.E_{1}$ = $\frac{hc}{\lambda} - \phi$

1 eV = $1.6 \times 10^{-19} J = \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{\lambda} - \phi$

$1.6 \times 10^{-19} J = \frac{1.98 \times 10^{-25} J.m}{\lambda} - \phi$ ........... (1)

From second source,

$K.E_{2}$ = $\frac{hc}{\lambda} - \phi$

$4 \times 1.6 \times 10^{-19} J = \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{\frac{\lambda}{2}} - \phi$

$6.4 \times 10^{-19} J = \frac{2 \times 1.98 \times 10^{-25} J.m}{\lambda} - \phi$ ........... (2)

Now, divide equation (2) by 2. Therefore, it will become

${6.4 \times 10^{-19}J}{2} = \frac{2 \times 1.98 \times 10^{-25} J.m}{2\lambda} - \frac{\phi}{2}$

$3.2 \times 10^{-19}J = \frac{1.98 \times 10^{-25} J.m}{\lambda} - \frac{\phi}{2}$ ......... (3)

Now, subtract equation (3) from equation (1), we get the following.

$1.6 \times 10^{-19} = \frac{\phi}{2}$

$\phi$ = $3.2 \times 10^{-19}$

= 2 eV

Thus, we can conclude that work function of the metal is 2 eV.

3 0

4 years ago

Which of the following statements best explains why ice floats on water

enot [183]

Answer:

c

Explanation:

Ice is about 9% less dense. When ice forms, it takes up about 9% more space than it did as a liquid. Thus, a 1 liter container of ice weighs less than a 1 liter container of liquid water, and the lighter material floats to the top.

4 0

3 years ago

Read 2 more answers

What happens when cells are exposed to radioactivity?

Step2247 [10]

Answer:

when cell is exposed to radiation we get brain tumour or cancer.

6 0

3 years ago

Read 2 more answers

Welding is an industrial process that is used to join pieces of metal. A certain mixture of gases used in welding is composed of

GarryVolchara [31]

The given question is incomplete. The complete question is :

Welding is an industrial process that is used to join pieces of metal. A certain mixture of gases used in welding is composed of carbon dioxide and argon. The partial pressure of carbon dioxide is 0.080 atm and the partial pressure of argon is 0.24 atm. What is the total pressure of the mixture.

Answer: 0.32 atm

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

$p_{total}=p_{CO_2}+p_{Ar}$