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Morgarella [4.7K]

4 years ago

9

Help me please with this

1 answer:

Gre4nikov [31]4 years ago

8 0

1. radiation
2. convection
3. condunction

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Explain how a theodolite works.

Oksana_A [137]

The theodolite is a precision measuring device used to measure horizontal and vertical angles. It works with a combination of: (1) optical plummets, which is used to ensure that it is placed exactly vertical above; (2) internal spirit, which ensures that it is levelled to the horizon; and (3) graduated circles, one vertical and one horizontal, which is used to measure actual angles. The mounted telescope can swivel horizontally and vertically. If this is adjusted correctly, accurate measurements can be obtained.

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3 years ago

A well chosen lifetime activity is something that should hold a person's interest for a long time.

Masteriza [31]

Answer:

true

Explanation:

as long as you are interested, you are happy

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3 years ago

When light of wavelength 240 nm falls on a cobalt surface, electrons having a maximum kinetic energy of 0.17 eV are emitted. Fin

dusya [7]

Answer:

(a) 5.04 eV (B) 248.14 nm (c) $1.21\times 10^{15}Hz$

Explanation:

We have given Wavelength of the light \lambda = 240 nm

According to plank's rule ,energy of light

$E = h\nu = \frac{hc}{}\lambda$

$E = h\nu = \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{ 240\times 10^{-9} m\times 1.6\times 10^{-19}J/eV}= 5.21 eV$

Maximum KE of emitted electron i= 0.17 eV

Part( A) Using Einstien's equation

$E = KE_{max}+\Phi _{0}$ , here $\Phi _0$ is work function.

$\Phi _{0}=E - KE_{max}$ = 5.21 eV-0.17 eV = 5.04 eV

Part( B) We have to find cutoff wavelength

$\Phi _{0} = \frac{hc}{\lambda_{cuttoff}}$

$\lambda_{cuttoff}= \frac{hc}{\Phi _{0} }$

$\lambda_{cuttoff}= \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{5.04 eV\times 1.6\times 10^{-19}J/eV }=248.14 nm$

Part (C) In this part we have to find the cutoff frequency

$\nu = \frac{c}{\lambda_{cuttoff}}= \frac{3\times 10^{8}m/s}{248.14 \times 10^{-19} m }= 1.21\times 10^{15} Hz$

5 0

3 years ago

An electric wheel chair is designed to run on a single 12-V battery rated to provide 100 ampere-hours. How much energy is stored

Paha777 [63]

Explanation:

It is given that,

Voltage of the battery, V = 12 V

Current, I = 100 ampere-hours

Energy stored is given by the product of power and time taken. So,

$E=P\times t$

P is the power, $P=V\times I$

$P=12\times 100$

P = 1200 watts

This power can be used for 1 hour or 3600 seconds

Energy, $E=1200\times 3600$

E = 4320000 J

So, the energy stored in this battery is 4320000 J. Hence, this is the required solution.

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3 years ago

A plane accelerates from 25 m/s to a velocity of 80 m/s in a time of 5 seconds. What

Natali [406]

Answer:

-7

Explanation:

-7 because -7 said so

6 0

3 years ago