Answer:
net power is + 2.25 D
Explanation:
Given data
distance vision = -0.25 D
near vision = + 2.50 D
to find out
net power
solution
we have given a person lens power for near is - 0.25 diopter and lens power for near power is +2.50 diopter so
net power is sum of both the power vision
so
net power = distance + near power
put both value we get net power
net power = ( -0.25 D) + ( + 2.50 D)
net power = + 2.25 D
so net power is + 2.25 D
Answer:
As collision is elastic,thus we can use conservation of momentum equation
mA=0.2 kg
(vB)1=0 m/s.......................as it is on rest before collision
(vA)1=4 m/s
(vA)2=-1 m/s
(vB)2=2 m/s
using equation
(mA*vA+mB*vB)1= (mA*vA+mB*vB)2
Where 1 and 2 represents before and after collision
(0.2*4)+(mB*0)=(0.2*-1)+(mB*2)
0.8=-0.2+(2mB)
mass of object B=mB=0.3 Kg
Answer:
B. Convection
D. Conduction
Explanation:
Conduction and convection are the two most prominent processes that helps transfer energy outward to the earth's crust.
- Energy within the core is a function of the radioactive decay and frictional heating.
- Also, heat that accreted during the formation of the earth is a significant source of internal energy.
- The heat is conducted away by the process of convection. This is possible due to temperature differences between different parts of the earth
- Conduction is made made possible due to the metallic bodies in the core and other part of the inner earth.
Answer:
No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings.
Explanation:
Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. There is no temperature change until a phase change is complete. The temperature of a cup of soda initially at 0ºC stays at 0ºC until all the ice has melted. Conversely, energy is released during freezing and condensation, usually in the form of thermal energy. Work is done by cohesive forces when molecules are brought together. The corresponding energy must be given off (dissipated) to allow them to stay together Figure 2.
The energy involved in a phase change depends on two major factors: the number and strength of bonds or force pairs. The number of bonds is proportional to the number of molecules and thus to the mass of the sample. The strength of forces depends on the type of molecules. The heat Q required to change the phase of a sample of mass m is given by
Q = mLf (melting/freezing,
Q = mLv (vaporization/condensation),
where the latent heat of fusion, Lf, and latent heat of vaporization, Lv, are material constants that are determined experimentally.
On an incline, the force causing the ball to move downwards would be gravity. Additionally, the component of gravity causing this ball to move downwards would be mgsintheta.
Hope this helps!
