Answer:
(c) +6.67
Explanation:
f1 = 10 cm
f2 = 20 cm
u = Object distance = 15 cm
Distance between lenses = 20 cm
For first lens image distance

Distance from second lens is 10 cm to the right

The final image will appear as +6.67 cm
Answer:
The object has 2 meter length. This means the length is any quantity with a dimension distance. The definition of the length is how long something is or amount of space. In the given data it is stated that, the object is something that has a length of 2 meter.
<em>Let's take examples to understand. </em>
For example a thread or a table is an object which has a total length of 2 meters.
Another example is something we are measuring it gives us a result of 2 meters of length by using a meter scale or meter tape.
Length is a measure of distance and it is a fundamental quantity. Meter is a international system of units (SI units).
Answer:
given,
mass of copper = 100 g
latent heat of liquid (He) = 2700 J/l
a) change in energy
Q = m Cp (T₂ - T₁)
Q = 0.1 × 376.812 × (300 - 4)
Q = 11153.63 J
He required
Q = m L
11153.63 = m × 2700
m = 4.13 kg
b) Q = m Cp (T₂ - T₁)
Q = 0.1 × 376.812 × (78 - 4)
Q = 2788.41 J
He required
Q = m L
2788.41 = m × 2700
m = 1.033 kg
c) Q = m Cp (T₂ - T₁)
Q = 0.1 × 376.812 × (20 - 4)
Q = 602.90 J
He required
Q = m L
602.9 = m × 2700
m =0.23 kg