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3 years ago

2. Express the following in SI units a) 0.009 cm? b) 25 km

Physics

1 answer:

pentagon [3]3 years ago

4 0

Answer:

a).

S.I units of length is meters. So we've to change cm → m

${ \rm{1 \: cm \: \dashrightarrow \: 0.01 \: m}} \\ { \rm{0.009 \: cm \: \dashrightarrow \: (0.009 \times 0.01)}} \\ \\ = { \underline{ \rm{ \: \: 0.00009 \: m \: \: }}}$

b).

km → m

${ \rm{1 \: km \: \dashrightarrow \: 1000 \: m}} \\ { \rm{25 \: km \: \dashrightarrow \: (25 \times 1000)}} \\ \\ = { \underline{ \rm{ \: \: 25000 \: m \: \: }}}$

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Two ions with masses of 4.39×10−27 kg move out of the slit of a mass spectrometer and into a region where the magnetic field is

Ilia_Sergeevich [38]

Answer:

7.2 cm

Explanation:

magnetic field, B = 0.301 T

speed, v = 7.92 x 10^5 m/s

mass, m = 4.39 x 10^-27 kg

q = 1.6 x 10^-19 C

The radius of singly changed ion is given by

$r = \frac{mv}{Bq}$

where, m is the mass of ion, v be the speed of ion, B is the magnetic field and q be the charge

$r = \frac{4.39\times 10^{-27}\times 7.92 \times 10^{5}}{0.301\times 1.6\times 10^{-19}}$

r = 0.072 m

r = 7.2 cm

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3 years ago

Ultraviolet light of wavelength 270 nm strikes a metal whose work function is 2.3 eV.What is the shortest de Broglie wavelength

soldier1979 [14.2K]

Answer:

The shortest de Broglie wavelength for the electrons that are produced as photoelectrons is 0.81 nm

Explanation:

Given;

wavelength of ultraviolet light, λ = 270 nm

work function of the metal, φ = 2.3 eV = 2.3 x 1.602 x 10⁻¹⁹ J = 3.685 x 10⁻¹⁹ J

The energy of the ultraviolet light is given by;

$E = \frac{hc}{\lambda}\\\\E = \frac{(6.626*10^{-34} )(3*10^{8}) }{270*10^{-9} }\\\\E = 7.362 * 10^{-19} \ J$

The energy of the incident light is related to kinetic energy of the electron and work function of the metal by the following equation;

E = φ + K.E

K.E = E - φ

K.E = (7.362 x 10⁻¹⁹ J) - (3.685 x 10⁻¹⁹ J )

K.E = 3.677 x 10⁻¹⁹ J

K.E = ¹/₂mv²

mv² = 2K.E

velocity of the electron is given by;

$V = \sqrt{\frac{2K.E}{m} }\\\\V = \sqrt{\frac{2(3.677*10^{-19}) }{9.1*10^{-31} } }\\\\V = 8.99*10^{5} \ m/s$

the shortest de Broglie wavelength for the electrons is given by;

$\lambda = \frac{h}{mv}\\ \\\lambda = \frac{6.626*10^{-34} }{(9.1*10^{-31})( 8.99*10^{5} )}\\\\\lambda = 8.10*10^{-10} \ m\\\\\lambda = 0.81 \ nm$

Therefore, the shortest de Broglie wavelength for the electrons that are produced as photoelectrons is 0.81 nm

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3 years ago

You are an electrician installing the wiring in a new home. The homeowner desires that a ceiling fan with light kits be installe

In-s [12.5K]

Answer:

3 fans per 15 A circuit

Explanation:

From the question and the data given, the light load let fan would have been

(60 * 4)/120 = 240/120 = 2 A.

Next, we add the current of the fan motor to it, so,

2 A + 1.8 A = 3.8 A.

Since the devices are continuos duty and the circuit current must be limited to 80%, then the Breaker load max would be

0.8 * 15 A = 12 A.

Now, we can get the number if fans, which will be

12 A/ 3.8 A = 3.16 fans, or approximately, 3 fans per 15 A circuit.

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3 years ago

Two permanent magnets produce a magnetic field pattern as shown below.

AlladinOne [14]

Answer:

S pole and S pole repelling

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3 years ago

A satellite completes one revolution of a planet in almost exactly one hour. At the end of one hour, the satellite has traveled

ad-work [718]

Answer:

shown below

Explanation:

2 x 10⁷ as a number is 20,000,000

20,000,000 - 10 = 19,999,990

It went 19,999,990 m/h

in km/h:

19,999,990 / 1000 = 19,999.99 km/h

in km/s

19,999,990 / 3,600,000 = ~5.56 km/s

in m/s

19,999,990 / 3600 = ~5555.56 m/s

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2 years ago

2. Express the following in SI units a) 0.009 cm? b) 25 km​

2. Express the following in SI units a) 0.009 cm? b) 25 km