Question
The present age of Preeti is twice Ruchi’s present
age. Six years ago, their average age was 15 years. What will be the Preeti’s age after five years?Solution
Let Ruchi’s present age be x. Preeti’s present age be 2x. Six years ago, their average age, [(x-6) + (2x-6)]/2= 15 3x – 12 = 30 x = 14 Preeti’s age after 5 years = 2x + 5 = 2 × 14 + 5 = 33 years.
Calculate the speed of light in diamond if its refractive index is 2.4.
(Speed of light = 3 × 10⁸ m/s)
A person throws a ball from ground level at speed u and angle θ. The ball reaches maximum height H and range R. What is the ratio H/R?
The colour of sky appears blue due to –
In an AC circuit, voltage and current are given by V = 200 sin(ωt) and I = 10 sin(ωt + π/3). What is the average power consumed?
If Planck’s constant h, gravitational constant G, and speed of light v are taken as fundamental units, the dimension of time is:
A body of mass 2 kg is moving with velocity 3 m/s. What is its kinetic energy?
An athlete can jump farther by running before jumping due to which type of inertia?
When a capacitor is fully charged in a DC circuit, the current through it is:
How long does an image remain on the retina after the object is removed?
The experimental evidence that the electron exhibits wave-like characteristics was first provided by:
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