List of practice Questions

Hydrocarbon used for welding purposes is:

Essential constituent of an amalgam is:

The common name of 2-Butanone is:

The number of molecules present in 2.8 g of nitrogen is:

Electronic configuration of copper can be represented as:

The half-life period of a radioactive element is 150 days. After 600 days, 1 gm of the element will be reduced to:

A wooden block of mass 6 kg is pulled across a rough surface by a 54 N force against a friction force \( F \). The acceleration of the block is \( 6 \, \text{m/s}^2 \). Then the value of friction force \( F \) is:

The gravitational force between two masses kept at a certain distance is \( P \) Newton. The same two masses are now kept in water and the distance between them is the same. The gravitational force between these two masses in water is \( Q \) Newton. Then:

An object is placed in front of a convex lens of focal length 12 cm. If the size of the real image formed is half the size of the object, then the distance of the object from the lens is:

An object of 4.0 cm in size is placed at 25 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image?

Heat (in calorie) required to increase the temperature from \( 10^\circ C \) to \( 20^\circ C \) of 6 kg copper is the same as the heat (in calorie) required to increase the temperature from \( 20^\circ C \) to \( 100^\circ C \) of 3 kg lead. If the specific heat of copper is 0.09, then the specific heat of lead will be:

\( V_V, V_R, V_G \) are the velocities of violet, red, and green light respectively, in a glass prism. Which among the following is a correct relation?

A body weighs 75 gm in air, 51 gm when completely immersed in an unknown liquid and 67 gm when completely immersed in water. Find the density of the unknown liquid:

100 joules of heat is produced each second in a 4 ohm resistance. Potential difference across the resistor is:

In a simple pendulum experiment, a student calculates the value of \( g = 9.92 \, \text{m/s}^2 \), but the standard value of \( g \) is \( 9.80 \, \text{m/s}^2 \). Then the percentage error in the calculation of \( g \) is:

A sound wave has a frequency of 500 Hz and wavelength 80 cm. How long will it take to travel 1 km?

A spherical mirror and a thin spherical lens each have a focal length of \( -15 \, \text{cm} \). The nature of the mirror and lens will be:

A stone is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of \( 10 \, \text{m/s}^2 \), with what velocity and after what time will it strike the ground?