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2 years ago

Human impact on the environment

Physics

1 answer:

Sergeeva-Olga [200]2 years ago

8 0

Answer:

we have caused global warming, we have caused the enhanced green house effect

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Pepsin is a digestive enzyme that Pepsin is a digestive enzyme that splits maltose into monosaccharides. is manufactured by the

LUCKY_DIMON [66]

Answer:

The correct option is: begins the hydrolysis of proteins in the stomach

Explanation:

Pepsin is a protease enzyme that is synthesized by the stomach. It is the main gastric enzyme that helps in the digestion of proteins molecules present in the food.

The pepsin enzyme catalyzes the acid hydrolysis of the peptide bond in the proteins at a very low acidic pH of 1.5-2.0.

This enzyme becomes inactive at pH 6.0 and gets fully denatured or irreversibly inactivated as the pH increases to 8.0.

8 0

2 years ago

Photoelectric effect:

Lynna [10]

Answer:

A. K = 0.546 eV

B. cooper and iron will not emit electrons

Explanation:

A. This is a problem about photoelectric effect. Then you have the following equation:

$K=h\nu-\Phi=h\frac{c}{\lambda} -\Phi$ (1)

K: kinetic energy of the ejected electron

Ф: Work function of the metal = 2.48eV

h: Planck constant = 4.136*10^{-15} eV.s

λ: wavelength of light = 410nm - 750nm

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

As you can see in the equation (1), higher the wavelength, lower the kinetic energy. Then, the maximum kinetic energy is obtained with the lower wavelength (410nm). Thus, you replace the values of all variables :

$K=(4.136*10^{-15}eV)\frac{3*10^8m/s}{410*10^{-9}m}-2.48eV\\\\K=0.546eV$

B. First you calculate the energy of the photon with wavelengths of 410nm and 750nm

$E_1=(4.136*10^{-15}eV)\frac{3*10^{8}m/s}{410*10^{-9}m}=3.02eV\\\\E_2=(4.13610^{-15}eV)\frac{3*10^{8}m/s}{750*10^{-9}m}=1.6544eV$

You compare the energies E1 and E2 with the work functions of the metals and you can conclude:

sodium = 2.3eV < E1

cesium = 2.1 eV < E1

cooper = 4.7eV > E1 (this metal will not emit electrons)

iron = 4.5eV > E1 (this metal will not emit electrons)

5 0

2 years ago

The primary difference between a barometer and a manometer is

Nitella [24]

Answer:

a barometer is used to measure atmospheric pressure, and a manometer is used to measure gauge pressure.

Explanation:

A barometer measures air pressure at any locality with sea level as the reference.

However, a manometer is used to measure all pressures especially gauge pressures. Thus, if the aim is to measure the pressure at any point below a fluid surface, a barometer is used to determine the air pressure. The manometer may now be used to determine the gauge pressure

The algebraic sum of these two values gives the absolute pressure.

4 0

2 years ago

A horizontal force of 90.0 N is required to push a 75kg object along a horizontal surface at a constant speed. What is the magni

Varvara68 [4.7K]

If the object is moving at a constant speed, acceleration is 0. So:

$F = ma

F = m\times 0

F = 0$

The resultant force is 0. So the force pushing the object must be equal to the friction force acting, so

Friction = 90 N

6 0

2 years ago

Isabela is an astronomer studying stars A and B. Star A is farther away from Isabela and yet when Isabela observes the stars, th

kakasveta [241]

Answer: star A is more luminous

Explanation:

7 0

2 years ago