JEE Main & Advanced
JEE Main Paper (Held On 11 April 2015)
question_answer
If a circle passing through the point (-1, 0) touches y-axis at (0, 2), then the length of the chord of the circle along the x-axis is :
[JEE Main Online Paper (Held On 11 April 2015)]
A)\[\frac{3}{2}\]
B)\[\frac{5}{2}\]
C) 3
D) 5
Correct Answer:
B
Solution :
AM = r - 1 \[\therefore \]Using pythogoras theorem is \[\Delta CAM\] \[{{2}^{2}}+{{\left( r-1 \right)}^{2}}={{r}^{2}}\] \[\Rightarrow \]\[4+{{r}^{2}}-2r+1={{r}^{2}}\] \[\Rightarrow \]\[4+{{r}^{2}}-2r+1={{r}^{2}}\]\[\Rightarrow \]\[r={}^{5}/{}_{2}\]\[\Rightarrow \]