It is given that for the convex lens,
Case 1.
u=−40cm
f=+15cm
Using lens formula
v
1
−
u
1
=
f
1
v
1
−
40
1
=
15
1
v
1
=
15
1
−
40
1
v=+24.3cm
The image in formed in this case at a distance of 24.3cm in left of lens.
Case 2.
A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens i.e. the source is placed at the focus of mirror, then the rays after reflection becomes parallel for the lens such that
u=∞
f=15cm
Now, using mirror’s formula
v
1
+
u
1
=
f
1
v
1
+
∞
1
=
15
1
v=+15cm
The image is formed at a distance of 15cm in left of mirror
Power = 
Delilah: 170J/30s = 5.66 W
Adam: 260J/20s = 13 W
Answer:
The direction of electric field and equipotential line at the same point are always PERPENDICULAR TO THE ELECTRIC FIELD.
Explanation:
Equipotential surface is a three dimensional part of equipotential lines.
Equipotential lines are a type of contour lines that is use to trace lines that have the same altitude on the map and the altitude is the electric potential.
Equipotential lines are always perpendicular to electric potential because the lines creates three dimension equipotential surface.
Answer:
143.352 watt.
Explanation:
So, in the question above we are given the following parameters or data or information that is going to assist us in answering the question above efficiently. The parameters are:
"A 1.8 m wide by 1.0 m tall by 0.65m deep home freezer is insulated with 5.0cm thick Styrofoam insulation"
The inside temperature of the freezer = -20°C.
Thickness = 5.0cm = 5.0 × 10^-2 m.
Step one: Calculate the surface area of the freezer. That can be done by using the formula below:
Area = 2[ ( Length × breadth) + (breadth × height) + (length × height) ].
Area = 2[ (1.8 × 0.65) + (0.65 × 1.0) + (1.8 × 1.0)].
Area = 7.24 m^2.
Step two: Calculate the rate of heat transfer by using the formula below;
Rate of heat transfer =[ thermal conductivity × Area (T1 - T2) ]/ thickness.
Rate of heat transfer = 0.022 × 7.24(25+20)/5.0 × 10^-2 = 143.352 watt.
