Physics 10

Take two oppositely charged rods, place them separately near small pieces of paper. Why do they both attract small pieces of paper? Is there any third type of charge on papers which attracts both positive and negative charges?

The pieces of paper are initially neutral. When a charged rod is brought near, it induces a charge separation in the paper—one side becomes slightly positive and the other slightly negative. Since opposite charges attract, the paper gets attracted to both positively and negatively charged rods. There is no third type of charge; it’s just … Read more

You take your car to a service station to get it polished. After a while, you observe that your car attracts dust. Why is dust attracted to the car?

When the car is polished, friction between the polishing cloth and the car’s surface can cause static charge buildup. This creates an electric field around the car, which attracts dust particles because they are either neutral or oppositely charged.   Related Questions: Rub a plastic ruler with your hair. Place it near running water from … Read more

Two identical spheres have the same masses. Then we charge both of them so they are oppositely charged. After charging, will both bodies have the same mass or different masses? Explain.

The masses will be slightly different. The sphere that gains electrons will have a slightly higher mass because electrons have a small mass. The sphere that loses electrons will have a slightly lower mass. However, the difference in mass is extremely small and usually negligible.   Related Questions: Rub a plastic ruler with your hair. … Read more

Rub a plastic ruler with your hair. Place it near running water from a tap. You see that the thin stream of water is deflected. Explain why.

When the plastic ruler is rubbed with hair, it gains a charge due to friction (electrostatic charging). Water molecules are polar, meaning they have positive and negative sides. The charged ruler attracts the oppositely charged ends of the water molecules, causing the stream of water to bend toward the ruler. Related Questions: Numerical Problems of … Read more

Calculate the frequency of red light of wavelength 700 nm in a vacuum.

Frequency of red light of wavelength 700 nm: The frequency f of light is given by the formula: f=c/λ​ Where: c=3×108 m/s (speed of light), λ=700 nm=700×10−9 m Substitute the values: f=3×108/700×10−9=3×108/7×10−7=4.29×1014 Hz Related Questions: A simple pendulum has a time period of 2 s. It is called a second pendulum. Find the length of a second pendulum on … Read more

n a ripple tank of length 1.6 m, waves cover this length in 2 seconds. If the distance between two consecutive troughs is 20 cm, find the number of waves, the frequency of the waves, and their time period.

Waves in a ripple tank: Given: Length of the tank L=1.6 m Time t=2 s Distance between consecutive troughs (wavelength) λ=20 cm=0.2 m The number of waves N can be found as: N=L/λ=1.6/0.2=8 The frequency f is: f=N/t=8/2=4 Hz The time period T is: T=1/f=1/4=0.25 s Related Questions: A simple pendulum has a time period of 2 s. It is called a … Read more

If 10 waves are produced on a long-stretched string of length 1 meter, what is the wavelength of the waves? What will be the frequency of the wave if the speed of the waves is 12 m/s?

Wavelength and frequency of waves: Given: Length of the string L=1 m 10 waves on the string. The wavelength λ is given by: λ=L/number of waves=1/10=0.1 m Given that the speed of the waves is v=12 m/s, we can find the frequency f using the wave speed formula: v=fλ Rearranging for f: f=v/λ f=12/0.1=120 Hz Related Questions: A simple pendulum has a … Read more