Q85.A man starts walking from the point ๐( - 3, 4 ) , touches the ๐ฅ-axis at ๐ , and then turns to reach at the point ๐( 0, 2 ) , The man is walking at a constant speed. If the man reaches the point ๐ in the minimum time, then 50 ( ๐๐ ) 2 + ( ๐ ๐) 2 is equal to ______ .
What This Question Tests
This question uses the reflection principle in coordinate geometry to find the path of minimum distance between two points via a line (x-axis), and then calculates a specified expression involving the lengths of segments.
Concepts Tested
Formulas Used
Reflection of (x,y) across x-axis is (x,-y)
Distance formula = sqrt((x2-x1)^2 + (y2-y1)^2)
๐ NCERT Sections This Tests
9.15 โ Apply Mirror Equation And The Condition:
Physics Class 12 ยท Chapter 9
9.15 Apply mirror equation and the condition: (a) f < 0 (concave mirror); u < 0 (object on left) (b) f > 0; u < 0 (c) f > 0 (convex mirror) and u < 0 (d) f < 0 (concave mirror); f < u < 0 to deduce the desired result.
9.8 โ A Beam Of Light Converges At A Point P. Now A Lens Is Placed In The
Physics Class 12 ยท Chapter 9
9.8 A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is (a) a convex lens of focal length 20cm, and (b) a concave lens of focal length 16cm?
2.1 โ Two Charges 5 ร 10โ8 C And โ3 ร 10โ8 C Are Located 16 Cm Apart. At
Physics Class 11 ยท Chapter 2
2.1 Two charges 5 ร 10โ8 C and โ3 ร 10โ8 C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.
๐ Question Details
- Chapter
- Coordinate Geometry
- Topic
- Reflection principle
- Year
- 2021
- Shift
- 01 Sep Shift 2
- Q Number
- Q85
- Type
- Numerical
- NCERT Ref
- Class 10 Mathematics Ch 7: Coordinate Geometry
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Q68.A light ray emerging from the point source placed at P(1, 3) is reflected at a point Q in the axis of x. If the reflected ray passes through the point R (6, 7), then the abscissa of Q is: (1) 1 (2) 3 (3) 7 (4) 5 2 2
Q76.If two vertices of an equilateral triangle are A(โa, 0) and B(a, 0), a > 0, and the third vertex C lies above x- axis then the equation of the circumcircle of โณABC is : (1) 3x2 + 3y2 โ2โ3ay = 3a2 (2) 3x2 + 3y2 โ2ay = 3a2 (3) x2 + y2 โ2ay = a2 (4) x2 + y2 โโ3ay = a2