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3 years ago

Copper has a specific heat capacity of 3.80 x 102 Jkg-1K-1 What temperature

Physics

1 answer:

erastovalidia [21]3 years ago

4 0

Answer:

4.91 K

Explanation:

From the question,

q = cm(Δt)................ Equation 1

Where q = heat, c = specific heat capacity of copper, m = mass of copper, Δt = temperature change.

make Δt the subject of the equation

Δt = q/cm.................. Equation 2

Given: q = 560 J, m = 300 g = 0.3 kg, c = 380 J/kg.K

Substitute these values into equation 2

Δt = 560(0.3×380)

Δt = 560/114

Δt = 4.91 K

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The metal cases of electrical appliances are connected to an earth wire.Which statement is not correct?A The live wire may becom

labwork [276]

Given that metal cases of electrical appliances are connected to the wire, let's select the statement which is not correct from the list of statements.

The earth wire is used to protect you and help reduce the risk of receiving an electric shock. The earth wire reduces the risk of electric shock by creating a path for a fault or lose current to flow to the Earth.

The Live wire may become loose and touch the metal case. In this case, the earth wire will channel the fault current to the earth thereby reducing the risk of electric shock.

If the metal case becomes live, the earth wire conducts current to the ground. This helps prevent electric shock from the metal case.

The Earth wire has low or no resistance. It is always made of copper.

It provides a low resistance path to the ground.

Therefore, the statement ''the earth wire needs to have high resistance'' is NOT current.

ANSWER:

C. The earth wire needs to have a high reistance.

7 0

1 year ago

How much heat is needed to change 1.25 kg of steak at 100°C to water at 100°C?

cricket20 [7]

The heat required to change 1.25 kg of steak is 2825 kJ /kg.

<u>Explanation</u>:

Given, mass m = 1.25 kg, Temperature t = 100 degree celsius

To calculate the heat required,

Q = m $\times$ L

where m represents the mass in kg,

L represents the heat of vaporization.

When a material in the liquid state is given energy, it changes its phase from liquid to vapor and the energy absorbed in this process is called heat of the vaporization. The heat of vaporization of the water is about 2260 kJ/kg.

Q = 1.25 $\times$ 2260

Q = 2825 kJ /kg.

7 0

4 years ago

The membrane that surrounds a certain type of living cell has a surface area of 4.3 x 10-9 m2 and a thickness of 1.1 x 10-8 m. A

Nadusha1986 [10]

Answer:

The charge resides on the outer surface = $1.245 \times 10^{-12}$ C

Explanation:

Surface area of cell $(A) = 4.3\times 10^{-9} m^{2}$

Separation between two plate $(d) = 1.1 \times 10^{-8} m$

Dielectric constant $(k) = 4.2$

Potential difference $(\Delta V) = 85.7 \times 10^{-3} V$

The capacitance of parallel plate capacitor in free space is given by,

$C = \frac{\epsilon_{o} A }{d}$

Where $\epsilon_{o} =$ permittivity of free space = $8.85 \times 10^{-12}$

The Capacitance of capacitor is increase by $k$ times when it placed in dielectric medium.

$C_{dielectric} = \frac{k \epsilon_{o} A }{d}$

And we know that, $C = \frac{Q}{ \Delta V}$

So charge on the outer surface is given by,

$Q = \frac{k \epsilon A \Delta V }{d}$

$Q = \frac{4.2 \times 4.3 \times 10^{-9} \times 8.85 \times 10^{-12} \times 85.7\times 10^{-3} }{1.1 \times 10^{-8} }$

$Q = 1.245 \times 10^{-12}$

3 0

4 years ago

What is pressure in physics

harkovskaia [24]

Pressure is the force per unit area. This means that the pressure a solid object exerts on another solid surface is its weight in newton’s divided by its area in square metres

8 0

3 years ago

A merry-go-round with a rotational inertia of 600 kg m2 and a radius of 3.0 m is initially at rest. A 20 kg boy approaches the m

nekit [7.7K]

Answer:

The velocity of the merry-go-round after the boy hops on the merry-go-round is 1.5 m/s

Explanation:

The rotational inertia of the merry-go-round = 600 kg·m²

The radius of the merry-go-round = 3.0 m

The mass of the boy = 20 kg

The speed with which the boy approaches the merry-go-round = 5.0 m/s

$F_T \cdot r = I \cdot \alpha = m \cdot r^2 \cdot \alpha$