2 years ago

Describe the formation of an image in a pinhole camera

Chemistry

1 answer:

Alla [95]2 years ago

8 0

Answer:

Explanation:

A pinhole camera is a simple camera without a lens but with a tiny aperture, a pinhole camera – effectively a light-proof box with a small hole in one side. Light from a scene passes through the aperture and projects an inverted image on the opposite side of the box, which is known as the camera obscura effect.

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Commercial cold packs often contain solid NH4NO3 and a pouch of water. The temperature of the pack drops as the NH4NO3 dissolves

Yanka [14]

Answer: b. $\Delta H_{soln}$ is positive and $\Delta S_{soln}$ is positive.

Explanation:-

As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of $NH_4NO_3$ in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e. $\Delta H_{soln}$ is positive.

The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e. $\Delta S_{soln}$ is positive.

$NH_4NO_3\rightarrow NH_4^++NO_3^-$