______ images are obtained when the plane mirror are kept parallel to the each other

Four power transistors, each dissipating 12 W, are mounted on a thin vertical aluminum plate 22 cm 3 22 cm in size. The heat gen

Sveta_85 [38]

Answer:

The temperature of the Aluminium plate 44.84⁰C

Explanation:

Number of transistors = 4

Since the heat dissipated by each transistor is 12W

Total heat dissipated, Q = 4 * 12 = 48 W

Q = 48 W

Cross sectional Area of the Aluminium plate, A = 2(l * b)

l = Length of the aluminium plate = 22 cm = 0.22 m

b = width of the aluminium plate = 22 cm = 0.22 m

A =2( 0.22 * 0.22 )

A = 0.0968 m²

From the heat balance equation, Q = hAΔT

h = 25 W/m²·K

A = 0.0968 m²

ΔT = T - T(air)

T(air) = 25°C

ΔT = T - 25°C

Q = 25 * 0.0968 * ( T - 25)

Q = 2.42 (T - 25)

Substitute Q = 48 into the equation above

48 = 2.42 (T - 25)

T - 25 = 19.84

T = 25 + 19.84

T = 44.84 ⁰C

6 0

3 years ago

A box is pulled 6 meters across the ground at a constant velocity by a horizontally applied force of 50 newtons. At the same tim

Vikentia [17]

Answer:

(a) Friction force = 50 N

(b) Work done by friction = 300 j

(c) Net work done = 0 j

Explanation:

We have given that the box is pulled by 6 meter so d = 6 m

Force applied on the box F = 60 N

We have have given that velocity is constant so acceleration will be zero

So to applied force will be utilized in balancing the friction force

So friction force $F_{friction}=50N$

Work done by friction force $W_{friction}=F_{friction}\times d=50\times 6=300j$

Work done by applied force $W=F\times d=50\times 6=300j$

So net work done = 300-300 = 0 j

7 0

2 years ago

The accepted standard measurement for mass is the A) liter. B) pound. C) Newton. D) kilogram.

andreev551 [17]

D) Kilograms is the standard unit of mass

6 0

3 years ago

The energy of an electromagnetic wave changes proportionally to which

ozzi

Answer:

D. Frequency

Explanation:

The energy of an electromagnetic wave is proportional to frequency, mathematically it is expressed as;

E ∝ f

E = hf

where;

h is Planck's constant = 6.626 x 10⁻³⁴ Js

The equation above can also be expanded to;

$E = hf = h \frac{c}{\lambda}$

where;

c is speed of light = 3 x 10⁸ m/s

λ is the wavelength of the electromagnetic wave

Since the speed of light is constant, we can conclude that the energy of the electromagnetic wave is directly proportional to its frequency and inversely proportional to its wavelength.

Therefore, the correct option for direct proportionality is FREQUENCY

8 0

2 years ago

The seeds were sown (change the voice)

MaRussiya [10]

Answer:

He sowed the seeds

Explanation:

While the question should have given the person who did the sowing for example the seeds were sown by him/ her/ the farmer/ or any name. Therefore, voice is given in passive and to change passive voice to active voice then the sentence will read as follows assuming that the seeds were sown by him

He sowed the seeds

7 0

2 years ago

______ images are obtained when the plane mirror are kept parallel to the each other​

______ images are obtained when the plane mirror are kept parallel to the each other