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Solution


Q.

Assertion (A): The length of the minute hand of a clock is 7 cm. Then the area swept by the minute hand in 5 minutes is 776 cm2.

Reason (R): The length of an arc of a sector of angle θ and radius r is given by l=2πr×θ360°
1 Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).  
2 Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).    
3 Assertion (A) is true but Reason (R) is false  
4 Assertion (A) is false but Reason (R) is true.  

Ans.

(2)

We have the length of the minute hand = 7 cm
∴ Radius of the sector of the circle = 7 cm 

and angle made by minute hand in 5 minutes = θ = 30°∴ Area swept by the minute hand in 5 minutes=30°360°×π×(7)2=112×227×7×7=776 cm2Also, the length of an arc of a sector of angle θ and radius r is given byl=2πr×θ360°∴ Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).