HELP PLEASEEEEEEEEEEEE

Explain why the speed of a sled is increases as it moves down a snow -covered hill, even though no one is pushing the sled

Andrews [41]

Hope this helps you.

6 0

3 years ago

White light, with frequencies ranging from 4.00 x 10^14 Hz to 7.90 x 10^14 Hz, is incident on a barium surface. Given that the w

REY [17]

Answer:

0.7515875 eV

$4\times 10^{14}\leq f$

Explanation:

f = Maximum frequency = $7.9\times 10^{14}\ Hz$

h = Planck's constant = $6.626\times 10^{-34}\ m^2kg/s$

W = Work function = 2.52 eV

Converting to Joules

$W=2.52\times 1.6\times 10^{-19}\\\Rightarrow W=4.032\times 10^{-19}\ J$

Maximum photon energy is given by

$E=hf\\\Rightarrow E=6.626\times 10^{-34}\times 7.9\times 10^{14}\\\Rightarrow E=5.23454\times 10^{-19}\ J$

Maximum Kinetic energy is given by

$K=E-W\\\Rightarrow K=5.23454\times 10^{-19}-4.032\times 10^{-19}\\\Rightarrow K=1.20254\times 10^{-19}\ J$

Converting to eV

$1.20254\times 10^{-19}\times \frac{1}{1.6\times 10^{-19}}=0.7515875\ eV$

The maximum kinetic energy of electrons ejected from this surface is 0.7515875 eV

$W=hf\\\Rightarrow f=\frac{W}{h}\\\Rightarrow f=\frac{4.032\times 10^{-19}}{6.626\times 10^{-34}}\\\Rightarrow f=6.08512\times 10^{14}\ Hz$

The range of frequencies for which no electrons are ejected is

$4\times 10^{14}\leq f$

5 0

3 years ago

What does it mean to say the mass is conserved during a physical change ?

Olin [163]

Mater doesn't just appear or disappeared. Chemical elements are still there just the connections and how it combines changes.

So what goes into your chemical eqation must still exist after the change.

4 0

3 years ago

Read 2 more answers

What material or device prevents the conducting of electricity?

PtichkaEL [24]

Answer:

Explanation:

An insulator. You can see ceramic insulators on telephone poles and power poles if you look carefully. If you live in a city, somewhere in that city is a power station. The insulators are huge. They have to be. The currents are very large in many cases.

4 0

3 years ago

In making water safe to drink, which process removes impurities by forcing water through sand or charcoal? A. aeration B. coagul

spin [16.1K]

The answer is C! I knew this way before taking the test

4 0

3 years ago