Physics

This is a multiple choice answer as classified in NCERT Exemplar

(c) 2Tsin $\theta$ -mg=0

2Tsin $\theta$ =mg

Total horizontal forces = Tcos $\theta -Tcos\theta =0$

T=mg/2sin $\theta$

As mg is constant T $\propto \frac{1}{sin\theta }$

T_max= mg/sin $\theta$ _min

Sin $\theta$ _min=0, $\theta$ _min= 0

T_min=mg/2sin $\theta$ _max

_{$sin\theta$ max}= 1, $\theta$ =90⁰

This is a multiple choice answer as classified in NCERT Exemplar

Y= $\frac{stress}{strain}=\frac{\frac{F}{A}}{\frac{?L}{L}}=\frac{F}{\pi ({D/2)}^2}*\frac{L}{?L}$

D²= $\frac{4FL}{\pi ?LY}$

D= $\sqrt[]{\frac{4FL}{\pi ?LY}}$

$\frac{D_{copper}}{D_{iron}}=\sqrt[]{\frac{Y_{iron}}{Y_{copper}}}$

This is a multiple choice answer as classified in NCERT Exemplar

(c) Consider the diagram where a spring is stretched by applying a load to its free end. Clearly the length and shape of the spring changes. The change in length corresponds to longitudinal strain and change in shape corresponds to shearing strain.

This is a multiple choice answer as classified in NCERT Exemplar

(d) Y young's modulus is inversely proportional to temperature, so if we increase temperature , young's modulus decreases.

This is a multiple choice answer as classified in NCERT Exemplar

(d) breaking stress = breaking force/area of cross section

Breaking force will not depend upon length.

This is a multiple choice answer as classified in NCERT Exemplar

(b) No frictional force exists in case of ideal fluid. Hence tangential forces are zero.

Yes, students can download the NCERT Exemplar PDF for Class 12 Physics Chapter 2. This offers various types of conceptual and application-based questions. Students can practice these offline at their own schedule. Practicing from PDF helps in improving problem-solving skills.

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