1.!(1)!A!hiker!determines!the!lengt h!of!a!lake!by!listening for!the!echo!of!her!shout!reflected !by!a! cliff!at!the!far!end of!the!lake.!She!hears!the!echo!2.0 !s!after!shouting.!Estimate the!length!of!the! lake.

The length of the lake is 340 meters.

Explanation:

It is given that, a hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 2 s after shouting. We need to find the length of the lake.

The distance covered by the person in 2 s is :

v is the speed of sound

The length of the lake is given by :

l = 340 meters

So, the length of the lake is 340 meters. Hence, this is the required solution.

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.

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