Solid State Physics

A descriptive experimental study was made in both air and water of the temporally periodic motion that occurs in the vortex whistle and cyclone separator. The motion can be described in terms of an oscillator that derives its energy from hydrodynamic instability of the steady swirling flow and whose frequency is determined by an angular velocity characteristic of this steady flow. The relevant dynamical parameters are the Rossby number and Reynolds number for the steady flow with the addition of the Strouhal number for the time-dependent flow. The results of this study were compared with the vortex breakdown phenomenon over swept-back wings. Breakdown can be described in the same terms as for the other two cases and it appears that all three motions are basically the same.

A bi-metallic strip bends when exposed to temperature changes due to the different thermal expansion coefficients of the metals it's made of. One metal expands more than the other, causing the strip to curve toward the metal with the higher coefficient when heated and in the opposite direction when cooled.

That is because of magnetic domains. Magnetic domains represent the magnetism at a given spot in the form of a direction. If the all point, let's say, left, the magnet's south pole will be on the left. Ex: LLLL If we were to split this magnet, we'd get LL LL, which is simply two smaller magnets.

No, not all metals are magnetic and not all non-metals are non-magnetic. Some metals, such as iron, nickel, and cobalt, are magnetic, while others like gold and aluminum are not. Similarly, some non-metals, like oxygen and carbon, can exhibit magnetic properties under certain conditions.

I do not have access to specific past papers, but you can visit the official website of Punjab University or contact the university's examination department to inquire about obtaining past papers for the BSc program. Additionally, you may also check online educational platforms or libraries that might have collections of past papers for reference and practice.

Water in its solid form, ice, is commonly used for preserving and storing perishable food items. It is also used in cooling systems and to aid in recovery for sports injuries. Additionally, ice sculptures are created as decorative pieces for events and celebrations.

Mass in an object describes the amount of matter contained within the object.

As a crystalline solid is heated, it undergoes a well-defined melting point where its ordered structure breaks down to a disordered liquid state. In contrast, an amorphous solid softens gradually upon heating without a distinct melting point, as its structure lacks long-range order. The amorphous solid may eventually become a viscous liquid upon further heating.

In order to explain black body radiation Max Planck had to introduce the idea that electromagnetic radiation was emitted in discrete packets or "quanta" rather than continuous waves. Each quantum had a fixed energy given by E = hf where h is a constant and f is the frequency.

as a material cools from a gas to a liquid, individual atoms or molecules slow down and get closer together. As it goes from a liquid to a solid, the molecules (or atoms) slow down more, and get closer together.

This is an example of thin-film interference. Oil on the pavement floats to the water's surface, forming an extremely thin film. Light waves reflected from the front and back surfaces of the film interfere, amplifying a particular light wavelength (color) for each particular film thickness. The rainbow pattern is formed by gradual changes in film thickness across the puddle surface.

it works on the same principle as an optical mouse..

an optical mouse uses an LED to track it's movements but laser mouse uses laser

The mouse emits a laser beam and then the reflected image is received by the CMOS sensor and sent to the DSP (Digital Signal Processor) .. this cycle happens multiple times in a second .The DSP detects patterns and changes in the images and tracks the movement of the mouse and then sends the coordinates to the computer..

a typical laser mouse is 2X or 3X more sensitive than optical mice

laser mice can be used on any surface as laser reflects off anything

however, optical mice can't be used on shiny surfaces like glass

Flow rate is volume of liqid flowing per unit time, velocity is displacement per unit time. For a constant cross-section area, the flow rate would increase with velocity and vice versa. This is because the volume flowing per unit time obviously increases if distance covered by the fluid increases.

Picture a fluid flowing through a cylindrical pipe.

The Moon averages 386,243km (240,000 miles) away from Earth. In theory that distance could be traveled in 3862 hours (161 days) at 100kph. In practical terms, you'd never get there from Earth. To escape Earth's gravity, a spacecraft needs to travel faster than 11.25 km (7 mi) per second. A speed of 100kph is only a fraction of that (about .027kps), so it wouldn't work. The Apollo Moon missions left the ground and accelerated to about 28000kph, until they entered a "parking orbit" of about 183.465km (114 miles) above the Earth's surface. They then left Earth orbit at about 39000kph. (The spacecraft decelerated on its own, during the trip.)

No, a pencil cannot be bent without breaking it because it is made of a rigid material like wood or plastic. Attempting to bend it will likely result in it snapping or fracturing.

Optical phonons are phonon polarization modes with a minimum frequency, regardless of wavelength, which occur in crystals with more than one atom per primitive cell.

Primitive cell is the early technological development....

A quantum in physics is a unit of measurement. It is the smallest discrete quantity of some physical property that a system or object can possess. It can, for example, be a discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents, or it may refer to momentum or electric charge or any other physical quantity of a substance.

Photosynthesis isn't a colour.

It is a process that happens in plants where the plant turns carbon dioxide into oxygen.

Carbon dioxide + Water (+Energy from the sun) = Oxygen + Glucose

It was simply a matter of availability and ease of processing at the time. Germanium was available and much easier to purify to the ultrapure level needed in semiconductors. It took well over a decade for the technology to progress to the point that silicon could also be purified to the ultrapure level needed in semiconductors. Once silicon could be used it quickly replaced germanium in most applications because it has several physical properties that are better than germanium.

An arb unit, short for "arbitrage unit," refers to a unit of measurement that quantifies the amount of mispricing in a financial market. It is typically used by traders engaged in arbitrage strategies to identify and exploit pricing discrepancies between related securities or assets. The arb unit helps traders evaluate the potential profit opportunities available through arbitrage trading.

Get two differently shaped messuring jugs, pour water into one up to a certain mark - then pour it from there into the other one conservation of mass should mean that it messures the same amount.

Cocaine makes you feel temporarily "up", followed by a crash "down". Coca-Cola is a soft drink which also is a stimulant; you get a boost of energy from the sugar and caffeine followed by a hypoglycemic "crash".

expands instead of contracts. This is due to water molecules forming a crystalline structure when freezing, creating a network that takes up more space than its liquid form. This unique behavior is why ice floats on water.