Select the correct answer

Many physical quantities are connected by inverse square laws, that is, by power functions of the form f(x)=kx^(-2). In particul

goldenfox [79]

Answer:

4 times

Explanation:

Since the equation for the illumination of an object, i.e. the brightness of the light, is <em>inversely proportional to the square of the distance from the light source</em>, the form of the function is:

f(x) = k.x⁻²

Where x is the distance between the object and the light force, k is the constant of proportionality, and f(x) is the brightness.

Then, if you move halfway to the lamp the new distance is x/2 and the new brightness (call if F) is :

$F=k(x/2)^{-2}=\frac{k}{(x/2)^2}= \frac{k}{x^2}. 4=f(x).4$

Then, you have found that the light is 4 times as bright as it originally was.

3 0

2 years ago

An American traveler in China carries a transformer to convert China's standard 220 V to 120 V so that she can use some small ap

Arisa [49]

Answer:

(a) The ratio of turns in the primary and secondary coils of her transformer is 1.833

(b) The ratio of input to output current is 0.55

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

Explanation:

Given;

input voltage, $V_p$ = 220 V

output voltage, $V_s$ = 120 V

General transformer equation is given as;

$\frac{V_p}{V_s} = \frac{N_p}{N_s} = \frac{I_s}{I_p}$

where;

Np is number of turns in the primary coil

Ns is number of turns in the secondary coil

Is - is the secondary current or output current

Ip - is the primary current or input current

(a) The ratio of turns in the primary and secondary coils of her transformer;

$\frac{N_p}{N_s} = \frac{V_p}{V_s} \\\\\frac{N_p}{N_s} = \frac{220}{120} = 1.833$

(b) The ratio of input to output current;

$\frac{I_p}{I_s} = \frac{V_s}{V_p} \\\\\frac{I_p}{I_s} = \frac{120}{220} \\\\\frac{I_p}{I_s} = 0.55$

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

8 0

2 years ago

a ball slows down as it rolls up hill this is an example of? neutral motion, relative velocity, positive acceleratio, negative a

Zarrin [17]

Answer: negative acceleration

Explanation:

Acceleration is speeding up, the ball is slowing down making it negative acceleration

8 0

3 years ago

Read 2 more answers

shepuryov [24]

I think it's three days. I read it in assignment potion before but it's kinds fuzzy but I believe it's three days. Hopefully thats correct.

4 0

3 years ago

The speed of water flowing through the 4in diameter section of the piping system is 3ft/s. What is the volume flow rate of water

olga_2 [115]

1 ft =12 in
4 in = 0.333 ft
volume = (п/4)*(0.333)² = 0.087 ft²
vol. flow = spead *volume
=3 ft/s * 0.087 ft²

vol flow = 0.261 ft³/s

3 0

3 years ago