An electrical heater 100 mm long and 5 mm in diameter is inserted into a hole drilled normal to the surface of a large block of
1 answer:
Answer:
Explanation:
Given data
length=100mm
Diameter=5mm
Thermal conductivity=5 W/m.K
Power=50 W
Temperature=25°C
The temperature of heater surface follows from the rate equation written as:
Where S can be estimated from the conduction shape factor for a vertical cylinder in semi infinite medium
Substitute the given values
The temperature of heater is then:
The temperature reached by the heater when dissipating 50 W with the surface of the block at a temperature of 25°C.
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Complete Question
How many turns are in its secondary coil, if its input voltage is 120 V and the primary coil has 210 turns.
The output from the secondary coil is 12 V
Answer:
The value is
Explanation:
From the equation we are told that
The input voltage is
The number of turns of the primary coil is
The output from the secondary is
From the transformer equation
Here is the number of turns in the secondary coil
=>
=>
=>
Answer:
The range of powers is
Explanation:
From the question we are told that
The far point of the left eye is
The near point of the left eye is
The near point with the glasses on is
From these parameter we can see that with the glass on that for near point the
Object distance would be
Image distance would be
To obtain the focal length we would apply the lens formula which is mathematically represented as
substituting values
converting to meters
Generally the power of the lens is mathematically represented as
Substituting values
From these parameter we can see that with the glass on that for far point the
Object distance would be
Image distance would be
To obtain the focal length of the lens we would apply the lens formula which is mathematically represented as
substituting values
converting to meters
Generally the power of the lens is mathematically represented as
Substituting values
This implies that the range of powers of the lens in his glass is