Question Library

The pitch of a sound is determined by its frequency. Higher frequencies correspond to higher pitches. For example, a high-pitched sound like a whistle has a higher frequency than a low-pitched sound like a drum.

The expression for the escape velocity \(v_e\) of an object from a planet of mass M and radius R using the universal gravitational constant G is: \(v_e = \frac{\sqrt{2GM}}{R}\)

An atom in an excited state is one whose electrons have moved to a higher energy level. In an atom, electrons are typically found in specific energy levels or orbitals. When an electron absorbs energy, it can move from a lower energy level to a higher energy level, which is referred to as an excited state. In this higher energy state, the electron is farther from the nucleus and has more potential energy. When the electron returns to its lower energy level, it emits the excess energy as electromagnetic radiation, often in the form of visible light. This is what gives rise to the characteristic spectral lines observed in spectroscopy.

V = 220V, P = 1.60KW = 1060W, I = ? P = IV I = \(\frac{P}{V} = \frac{1060}{220}\) ≈ 5A.

v = 120m/s, \lambda = 0.50m, f = ? v = f\lambda f = \(\frac{v}{\lambda} = \frac{120}{0.50}\) Therefore, = 240Hz.

The diagram above is a full wavelength and the length of an open pipe during first overtone equals one wavelength i.e. l = \lambda

The process of producing electric current by a changing magnetic field is referred to as electromagnetic induction. Electromagnetic induction is a phenomenon in which a voltage is generated in a conductor when it is exposed to a changing magnetic field. This voltage can then be used to drive an electric current.

In a controlled thermal fission reactor, control rods are used to absorb excess neutrons and thus control the rate of the nuclear reaction. They do not affect the speed of the neutrons released on fission. The speed of the neutrons is determined by the nature of the fission process itself, not by the control rods.

u = 20 ms-1, t = 15 s \(S = ut + 1/2 at^2\) S = 20(15) + \(\frac{1}{2}\times a \times 15^2\) ∴ S = 300 + 225\(\frac{a}{2}\)

The forces opposing the motion of the device are "mgsin \theta" and "\muN" where N is the normal reaction From the diagram, on resolving to components, N = mgcos \theta Total opposing force = mgsin \theta + \mumgcos \theta = mg(sin \theta + \mucos \theta) = 100 \times 10 \times (sin 30^\circ + 0.25 \times cos 30^\circ) = 1000 \times (0.5 + 0.2165) = 1000 \times 0.7165 = 716.5 N

Inserting a brass rod in the test tube will not increase the strength of the magnetic field of the solenoid. The strength of the magnetic field inside a solenoid depends on factors such as the number of turns of wire, the current passing through it, and the core material within the solenoid. Materials with high permeability, like soft iron and steel, can enhance the strength of the magnetic field when inserted into the solenoid. Nickel, which also has some ferromagnetic properties, would have a similar effect. However, brass is not a ferromagnetic material; it does not enhance the magnetic field strength when inserted into the solenoid. In fact, it might even slightly reduce the magnetic field strength due to its non-magnetic properties.

The statement that is not an advantage of a solid dielectric material between the plates of a capacitor is: it increases the electrical conduction of the capacitor. In fact, one of the primary advantages of using a solid dielectric material between the plates of a capacitor is that it reduces electrical conduction between the plates. Dielectric materials are insulators, and they prevent the flow of electric current between the plates, thus increasing the capacitor's ability to store charge.

The device used to compare the relative magnitudes of charges on two given bodies is a gold leaf electroscope. A gold leaf electroscope consists of two thin gold leaves that are attached to a metal rod inside a glass or plastic enclosure. When a charged object is brought near the metal rod, it induces a charge on the leaves. The leaves, being like charges, repel each other and spread apart. By observing the degree to which the leaves separate, you can compare the relative magnitudes of charges on different bodies. This makes a gold leaf electroscope a valuable tool for demonstrating the presence and relative strength of electric charges.

The instrument used to measure relative humidity is a hygrometer. Relative humidity is the amount of moisture in the air compared to the maximum amount of moisture the air could hold at the same temperature. A hygrometer is a device used for measuring the moisture content in the atmosphere, soil, or confined spaces.

u = 0, g = 10 \(ms^2\), v = 5 m/s, h = ? From \(v^2 = u^2 + 2gh\) ⇒ \(5^2 = 0^2 + 2 \times 10 \times h\) 25 = 0 + 20h 25 = 20h Therefore, h = \(\frac{25}{20}\) = 1.25m