Physics

Mass is defined as the amount of matter in an object, distinguishing it from volume, density, or space. Therefore, the correct answer is Mass.

Rails are joined with a gap to allow for thermal expansion during hot weather. Without this gap, the rails could buckle or deform, causing accidents. Thus, the gap prevents accidents due to expansion in summer.

According to the theory of relativity, clocks moving at velocities close to the speed of light run slower compared to those at rest. This phenomenon is known as time dilation.

Sound requires a medium (solid, liquid, or gas) to travel because it propagates through vibrations of particles. A vacuum lacks particles, so sound cannot travel through it.

The speed of light in vacuum is approximately 186,000 miles per second, which corresponds to option A. This is a well-established physical constant.

When white light passes through a prism, it disperses into seven distinct colors: red, orange, yellow, green, blue, indigo, and violet. This phenomenon is due to the different wavelengths of light bending by different amounts.

Sound waves are longitudinal waves because the particle displacement is parallel to the direction of wave propagation, causing compressions and rarefactions in the medium.

When a wire of resistance R is cut into two equal halves, each half has resistance R/2. Connecting these two halves in parallel results in a combined resistance of (R/2 * R/2) / (R/2 + R/2) = R/4. Since the original resistance is 6 ohms, the new resistance is 6/4 = 1.5 ohms, which corresponds to option C (R/4).

The audible frequency range for humans is approximately 20 Hz to 20,000 Hz. The shortest wavelength corresponds to the highest frequency, which is 20,000 Hz. Using the speed of sound in air as approximately 340 m/s, the wavelength is calculated by the formula wavelength = speed / frequency. Thus, wavelength = 340 m/s / 20,000 Hz = 0.017 m = 1.7 cm. Therefore, the correct answer is option B (1.7 cm). The original explanation had the correct calculation but incorrectly marked option C (1.6 cm) as the answer. The correct answer should be B.

The term 'Slinky Approximation' is used in physics modeling of slinkies to describe the approximation where the natural (unstretched) length of the slinky is very small compared to its stretched length under gravity. This is also called the 'perfectly elastic' approximation. Under this approximation, the unstretched length is negligible, and the tension in the slinky can be treated as approximately constant horizontally. This leads to simplified equations describing the slinky's stretched length and behavior. This approximation is characteristic of slinkies because their coils are tightly packed when unstretched, making the original length very small compared to the stretched length. Therefore, the 'Slinky Approximation' correctly refers to the scenario where the original length is very small compared to the final stretched length, matching option C. The other options like 'Elastic Approximation' or 'Non-Elastic Approximation' are not standard terms used to describe this scenario.