Answer:
1.0 dioptres
Explanation:
Farsightedness is an eye defect in which a person can see far objects clearly but not near objects. That implies that the patients' near point is farther than 25cm which is the normal least distance of distinct vision.
Farsightedness results from the eyeball being too long or the crystalline lens not being sufficiently converging.
Carol is farsighted with a near point of about a meter (100cm). We desire to make a lens to enable her near point be reduced to about 50cm. The focal length and power of this lens is calculated in the image attached.
The power of a lens is the inverse of its focal length in meters hence the 100 in the formula for power of the lens.
Answer:
-1786.5J
Explanation:
Temperature 1=T1=25°c
Temperature 2=T2=200°c
Pressure P1=1bar
Pressure P2=0.5bars
T=37°c+273=310k
Note number if moles=1
Recall work done =2.3026RTlogp2/P1
2.3026*8.314*310log(0.5/1)
-1786.5J
194db is the loudest Sound wave
Answer:
t = 4.0 min
Explanation:
given data:
diameter of rod = 2 cm
T_1 = 100 degree celcius
Air stream temperature = 20 degree celcius
heat transfer coefficient = 200 W/m2. K
WE KNOW THAT
copper thermal conductivity = k = 401 W/m °C
copper specific heat Cp = 385 J/kg.°C
density of copper = 8933 kg/m3
charateristic length is given as Lc
Biot number is given as 
Bi = 0.0025
As Bi is greater than 0.1 therefore lumped system analysis is applicable
so we have
............1
where b is given as
b = 0.01163 s^{-1}
putting value in equation 1
solving for t we get
t = 4.0 min
