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alekssr [168]
3 years ago
7

i) A 100 W and 60 W bulb are joined in series and connected to the mains. Which bulb will glow brighter? Why? ii) A 100 W and a

60 W bulb are joined in parallel to the mains. Which bulb will glow brighter? Why?
Physics
1 answer:
Reika [66]3 years ago
7 0

Answer:

i) 60 W

ii) 100 W

Explanation:

In each case, the bulb that dissipates the most power is the bulb that glows brighter.  Power is voltage times current (P = VI).  Using Ohm's law, we can rewrite this as P = I²R or P = V²/R.

Bulbs are rated at a certain power for a certain voltage.  P = V²/R, so the bulb with the lower resistance will have the higher power rating.  Therefore, the 100 W bulb has a lower resistance than the 60 W bulb.

i) They are in series, so they have the same current.  P = I²R, so the bulb with the higher resistance will glow brighter.  That's the 60 W bulb.

ii) They are in parallel, so they have the same voltage.  P = V²/R, so the bulb with the lower resistance will glow brighter.  That's the 100 W bulb.

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Como estan formados los musculos?
VikaD [51]

Answer:

Explanation: El músculo esquelético está formado por fibras musculares, rodeadas de una capa de tejido conjuntivo, denominada endomisio. Las fibras se reúnen en fascículos primarios, que también están rodeados por otra capa de tejido conjuntivo, esta vez, más grueso, denominada perimisio.

3 0
3 years ago
Read 2 more answers
If the period of the pendulum is tripled, what is the length of the string increased by?
Nitella [24]
The period of the pendulum doesn't determine the length of the string. 
It's the other way around.

The period of the pendulum is proportional to the square root of its length.
So if you want to triple the period, you have to make the string nine times
as long as it is now.
7 0
3 years ago
A 55.0-g sample of hot metal initially at 99.5oC was added to 40.0 g of water in a Styrofoam coffee cup calorimeter. The water a
Kaylis [27]

Answer:

Cp= 0.44 J/g.C

This is heat capacity of metal.

Explanation:

From energy conservation

Heat lost by metal = Heat gain by water +Heat gain by  calorimeter

Because here temperature of metal is high that is why it loose the heat.The temperature of water and  calorimeter is low that is why they gain the heat.

final temperature is T= 30.5 C

We know that sensible heat transfer given as

Q= m Cp ΔT

m=Mass

Cp=Specific heat capacity

ΔT=Temperature difference

By putting the values

55 x Cp ( 99.5 - 30.5) = 40 x 4.184 ( 30.5- 21 ) + 10 x ( 30.5 - 21)

Cp ( 99 .5- 30.5) = 30.65

Cp= 0.44 J/g.C

This is heat capacity of metal.

4 0
3 years ago
Strontium−90 is one of the products of the fission of uranium−235. This strontium isotope is radioactive, with a half-life of 28
Ludmilka [50]

Answer : The time passed in years is 20.7 years.

Explanation :

Half-life = 28.1 years

First we have to calculate the rate constant, we use the formula :

k=\frac{0.693}{t_{1/2}}

k=\frac{0.693}{28.1\text{ years}}

k=2.47\times 10^{-2}\text{ years}^{-1}

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 2.47\times 10^{-2}\text{ years}^{-1}

t = time passed by the sample  = ?

a = initial amount of the reactant  = 1.00 g

a - x = amount left after decay process = 0.600 g

Now put all the given values in above equation, we get

t=\frac{2.303}{2.47\times 10^{-2}}\log\frac{1.00}{0.600}

t=20.7\text{ years}

Therefore, the time passed in years is 20.7 years.

8 0
3 years ago
If a chemical reaction has a AH value of -125 kJ, it would be considered what?
egoroff_w [7]

exothermic

Explanation:

negative means it's losing energy

4 0
2 years ago
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