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3 years ago

Which phenomenon generates electric current?

Physics

2 answers:

Dimas [21]3 years ago

7 0

Answer:

D Photoelectric effect

Explanation:

When light of a certain frequency which is above the cut off frequency is incident on a metal, electrons are emitted from its surface. These electrons are called photo electrons. The number of photo electrons released will depend on the intensity of the incident light. This flow or release of electrons develops an emf and is called as the photoelectric current.

Applications of photoelectric current include photo conductive cells, photoemissive cells, solar cells etc.

grigory [225]3 years ago

3 0

The one that does that is the photoelectric effect. This allows the sun to hit the surface and produces enough energy for electrons to be knocked off the atom and allows a current to move.

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A woman pushes an oak chest across an oak floor at a constant speed of 0.450 m/s. The chest has a mass of 40.0 kg, and the coeff

natima [27]

Answer:

A. 243 N

Explanation:

Friction is the force that opposes the relative motion between systems that are in contact.

This friction force that opposes the motion of the oak chest across the oak surface will be equal and opposite to that exerted by the woman.

First find the normal force which is the force that would point directly upwards to support weight of the block.

Normal force, N= mg where m is the mass of the chest and g is the acceleration due to gravity.

Given m=40 kg and g=9.80 m/s²

N force=40×9.80 =392N

Then find the force of friction which is given by the formula;

<em>F=μN where μ is friction coefficient for the oak chest and N is the normal force on the chest</em>

Given <em>μ</em>=0.620 and N force = 392 N then it will be;

F=0.620× 392 =243.04 N

Answer : 243 N

6 0

3 years ago

If the energy bar was his only fuel, how far could a 68 kg person walk at 5 km/h?

goldfiish [28.3K]

An energy bar contains of 20grams of carbohydrates and 1gram is equal to 17 KJ. If the energy bar was his only fuel the total energy available is equal to (17,000 x 20) = 340,000j. Estimate KJ per hour is equal to 1539KJ, it has Time equal to (340,000/1539,000) is equal to 0.2209 hour and his Distance is equal to (5,000 x .2209) = 1.1045km.

3 0

3 years ago

A transformer consists of 290 primary windings and 824 secondary windings. Part A: If the potential difference across the primar

jasenka [17]

Answer:

Part 1) Voltage in secondary windings is 61.08 Volts

Part 2) Current in secondary windings is 0.53 Amperes

Explanation:

The potential developed in the primary and secondary winding of a transformer are related as

$\frac{N_{p}}{N_{s}}=\frac{V_{p}}{V_{s}}$

where

Np no of turns in primary coil

Ns no of turns in secondary coil

Vp Voltage of turns in primary coil

Vs Voltage of turns in secondary coil

Applying values in the formula we get

$\frac{290}{824}=\frac{21.5}{V_{s}}\\\\\therefore V_{s}=21.5\times \frac{824}{290}=61.08V$

Part 2)

Using Ohm's law the current is given by

$I=\frac{V_{s}}{R}\\\\I=\frac{61.089}{115}=0.53A$

5 0

3 years ago

The sides of a rectangle are 6.01 meters and 12 meters. Taking the significant figures into account, what is the area of the rec

Anit [1.1K]

Answer: The area of the rectangle is 72.12 square meters

Explanation:

The area of the rectangle is length x width

Area = 6.01 m x 12 m = 72.12 m²

4 0

3 years ago

A swimmer moves through the water at 2.5 meters per second and experiences a drag force of 240 N. How much power is she generati

mote1985 [20]

-- There's a force of 240N pushing her backwards.

-- She's maintaining a steady speed (of 2.5 m/s) .

-- In order to maintain a steady speed (no acceleration),
the forces on her must be balanced. So she's maintaining
a steady force of 240N forward.

-- Every time she moves 1 m forward, she does work of
(force) x (distance) = 240 joules.

-- She moves 2.5 meters forward every second.
So she's doing (240 x 2.5) = 600 joules of work every second.

-- 600 joules per second = 600 watts .

6 0

3 years ago