1.

A body cools in a surrounding which is at a constant temperature of \[{{\theta }_{0}}\]. Assume that it obeys Newton's law of cooling. Its temperature\[\theta \]is plotted against time t. Tangents are drawn to the curve at the points\[P\left( \theta ={{\theta }_{2}} \right)\]and\[Q\left( \theta ={{\theta }_{1}} \right)\]. These tangents meet the time axis at angle of\[{{\phi }_{2}}\] and \[{{\phi }_{1}}\], as shown, then

A. \[\frac{\tan {{\phi }_{2}}}{\tan {{\phi }_{1}}}=\frac{{{\theta }_{1}}-{{\theta }_{0}}}{{{\theta }_{2}}-{{\theta }_{0}}}\]
B. \[\frac{\tan {{\phi }_{2}}}{\tan {{\phi }_{1}}}=\frac{{{\theta }_{2}}-{{\theta }_{0}}}{{{\theta }_{1}}-{{\theta }_{0}}}\]
C. \[\frac{\tan {{\phi }_{1}}}{\tan {{\phi }_{2}}}=\frac{{{\theta }_{1}}}{{{\theta }_{2}}}\]
D. \[\frac{\tan {{\phi }_{1}}}{\tan {{\phi }_{2}}}=\frac{{{\theta }_{2}}}{{{\theta }_{1}}}\]
Answer» C. \[\frac{\tan {{\phi }_{1}}}{\tan {{\phi }_{2}}}=\frac{{{\theta }_{1}}}{{{\theta }_{2}}}\]


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