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3 years ago

11

How do i ask a question on brainly?

2 answers:

goldfiish [28.3K]3 years ago

6 0

Answer:

just do what u did to post this question

Explanation:

lol

igor_vitrenko [27]3 years ago

4 0

Answer:

you ask a question

Explanation:

You might be interested in

If the primary of a transformer were connected to a dc power source,

QveST [7]

Answer:

D. only briefly while being connected or disconnected.

Explanation:

As we know that transformer works on the principle of mutual inductance

here we know that as per the principle of mutual inductance when flux linked with the primary coil charges then it will induce EMF in secondary coil

So here when AC source is connected with primary coil then it will give output across secondary coil because AC source will have change in flux with time.

Now when we connect DC source across primary coil then it will not induce any EMF across secondary coil because DC source is a constant voltage source in which flux will remain constant always

So here in DC source the EMF will only induce at the time of connection or disconnection when flux will change in it while rest of the time it will give ZERO output

so correct answer will be

D. only briefly while being connected or disconnected.

8 0

3 years ago

When a current flows in an aluminum wire of diameter 2.91 mm 2.91 mm , the drift speed of the conduction electrons is 0.000191 m

charle [14.2K]

Answer:

Number of electrons are flowing per second is 2.42 x 10¹⁹

Explanation:

The electric current flows through a wire is given by the relation :

$I=envA$ ....(1)

Here I is current, e is electronic charge, v is drift velocity of electrons and A is the Area of the wire.

But electric current is also define as rate of electrons passing through junction times their charge, i.e. ,

$I=Ne$ ....(2)

Here N is the rate of electrons passing through junction.

From equation (1) and (2).

$eN = envA$

$N=nvA$

But area of wire, $A=\pi \frac{d^{2} }{4}$

Here d is diameter of wire.

So, $N = nv\pi \frac{d^{2} }{4}$

Substitute 2.91 x 10⁻³ m for d, 0.000191 m/s for v and 6 x 10²⁸ m⁻³ for n in the above equation.

$N = 6\times10^{28}\times 0.000191\times\pi \frac{(2.91\times10^{-3} )^{2} }{4}$

N = 2.42 x 10¹⁹ s⁻¹

8 0

3 years ago

List things in your house and put them in order of density

ELEN [110]

I don't know what's in your house! lol. try naming things like: ball, lamp, cup, bowl.

3 0

3 years ago

Read 2 more answers

A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in

butalik [34]

Answer:

copper will have more change in temperature as compare with aluminum

Explanation:

Hot piece of copper is made in contact with cold piece of aluminium

So here thermal energy transfer will take place from copper to aluminium

so by energy conservation we can say that heat given by copper is same as the heat absorbed by aluminium.

now we have

$m_1s_1\Delta T_1 = m_2s_2\Delta T_2$

here we know that

$s_1$ = specific heat capacity of copper

$s_2$ = specific heat capacity of aluminum

given that specific heat capacity of aluminium is more than double that of copper

so we can say

$s_2 = 2s_1$

so here if the mass of copper and aluminium is same then

$\Delta T_1 = 2 \Delta T_2$

so temperature change of copper is twice the temperature change of aluminium

So copper will have more change in temperature as compare with aluminum

4 0

3 years ago

A box, compressing a spring by 4 m, is loaded and ready. Moments later the 8.0 kg box has been launched with

Mrac [35]

Answer:

50 N/m

Explanation:

Elastic energy = kinetic energy

EE = KE

½ kx² = ½ mv²

½ k (4 m)² = ½ (8.0 kg) (10.0 m/s)²

k = 50 N/m

3 0

3 years ago