What tool should a scientist use to measure an object in milligrams

The work function of a metal surface is 4.80 × 10-19 J. The maximum speed of the electrons emitted from the surface is vA = 7.7

poizon [28]

Answer:

$\lambda_A=2.65177\times 10^{-7}\ m$

$\lambda_B=3.32344\times 10^{-7}\ m$

Explanation:

h = Planck's constant = $6.63\times 10^{-34}\ m^2kg/s$

c = Speed of light = $3\times 10^8\ m/s$

m = Mass of electron = $9.11\times 10^{-31}\ kg$

$W_0$ = Work function = $4.8\times 10^{-19}\ J$

$v_A$ = Velocity of A particle = $7.7\times 10^5\ m/s$

$v_B$ = Velocity of B particle = $5.1\times 10^5\ m/s$

The wavelength is given by

$\lambda=\frac{hc}{\frac{1}{2}mv^2+W_0}$

$\lambda_A=\frac{6.63\times 10^{-34}\times 3\times 10^8}{\frac{1}{2}9.11\times 10^{-31}(7.7\times 10^5)^2+4.8\times 10^{-19}}\\\Rightarrow \lambda_A=2.65177\times 10^{-7}\ m$

The wavelength $\lambda_A=2.65177\times 10^{-7}\ m$

$\lambda_B=\frac{6.63\times 10^{-34}\times 3\times 10^8}{\frac{1}{2}9.11\times 10^{-31}(5.1\times 10^5)^2+4.8\times 10^{-19}}\\\Rightarrow \lambda_B=3.32344\times 10^{-7}\ m$

The wavelength $\lambda_B=3.32344\times 10^{-7}\ m$

5 0

4 years ago

A German scientist, George Ohm, discovered the relationship between current, voltage, and resistance. This became known as Ohm's

Korvikt [17]

Choice A ... I = V/R ... is a correct form of Ohm's Law.

3 0

3 years ago

Read 2 more answers

The intensity of sunlight reaching the earth is 1360 w/m2. Assuming all the sunligh is absorbed, what is the radiation pressure

krok68 [10]

(a) $1.15\cdot 10^9 N$

For an electromagnetic wave incident on a surface, the radiation pressure is given by (assuming all the radiation is absorbed)

$p=\frac{I}{c}$

where

I is the intensity

c is the speed of light

In this problem, $I=1360 W/m^2$ ; substituting this value, we find the radiation pressure:

$p=\frac{1360 W/m^2}{3\cdot 10^8 m/s}=4.5\cdot 10^{-6} Pa$

the force exerted on the Earth depends on the surface considered. Assuming that the sunlight hits half of the Earth's surface (the half illuminated by the Sun), we have to consider the area of a hemisphere, which is

$A=2pi R^2$

where

$R=6.37\cdot 10^6 m$

is the Earth's radius. Substituting,

$A=2\pi (6.37\cdot 10^6 m)^2=2.55\cdot 10^{14}m^2$

And so the force exerted by the sunlight is

$F=pA=(4.5\cdot 10^{-6} Pa)(2.55\cdot 10^{14} m^2)=1.15\cdot 10^9 N$

(b) $3.2\cdot 10^{-14}$

The gravitational force exerted by the Sun on the Earth is

$F=G\frac{Mm}{r^2}$

where

G is the gravitational constant

$M=1.99\cdot 10^{30}kg$ is the Sun's mass

$m=5.98\cdot 10^{24}kg$ is the Earth's mass

$r=1.49\cdot 10^{11} m$ is the distance between the Sun and the Earth

Substituting,

$F=(6.67\cdot 10^{-11} )\frac{(1.99\cdot 10^{30}kg)(5.98\cdot 10^{24} kg)}{(1.49\cdot 10^{11} m)^2}=3.58\cdot 10^{22}N$

And so, the radiation pressure force on Earth as a fraction of the sun's gravitational force on Earth is

$\frac{1.15\cdot 10^9 N}{3.58\cdot 10^{22}N}=3.2\cdot 10^{-14}$

6 0

4 years ago

A constant net torque is exerted on an object. Which of the following quantities for the object cannot be constant? (Select all

prohojiy [21]

Answer:

A. kinetic energy

B. angular velocity

E. angular position

Explanation:

The quantities that cannot be constant if a constant net torque is exerted on an objecta are:

A. Kinetic energy. If a torque is applied, the linear or angular speed will be changing at a rate proportional to the torque, so the kinetic energy will change too.

B. Angular velocity. It will change at a rate equal to the torque.

C. Angular position. If the angular velocity changes, the angular position will change.

3 0

4 years ago

8 ( 3b + 3 ) = 5b + 5

Sophie [7]

You first distribute 8 through the parenthesis so it’s 24b+24=5b+5
Then collect the like terms to calculate 24b-5b=5-24 you then subtract so now it’s 19b=-9
So now you divide and your answer is b=-1

4 0

3 years ago