HRS - Ask. Learn. Share Knowledge. Logo

Questions in physics

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] Cosmology studies the universe as a whole and how it develops over time: The scale factor [tex]a(t)[/tex] describes the change of distance in the universe. The Hubble parameter [tex]H(t)=\dot{a}(t) / a(t)[/tex] (where the dot represents the rate of change with respect to time) describes the rate at which the universe expands, and was measured to be around [tex]72.6 km / s / Mpc[/tex] using the James Webb Space Telescope in 2024. The deceleration parameter [tex]q[/tex] describes the acceleration of the expansion: [tex]q=-\left(1+\frac{\dot{H}}{H^2}\right)[/tex] Assume a model with [tex]a(t)=\lambda \cdot t^\beta[/tex], where [tex] \lambda[/tex] and [tex]\beta[/tex] are real numbers. Knowing that the universe is around 13.7 billion years old, determine if the expansion is accelerating or decelerating.

[Done] What is $h$ called in the equation $E=\frac{h c}{\lambda}$? A. The speed of light B. Einstein's constant C. The EM constant D. Planck's constant

[Done] a) V² b)² 73. What is Transformer? a) Transformer is a device used to convert low alternating voltage to high alternating voltage b) Transformer is a device used to convert alternating current to direct current c) Transformer is a device used to convert low alternating current to a high alternating current d) Transformers are used only for low alternating voltage sens in the star Diffusion

[Done] What is the mass of a sample of water that takes 2000 kJ of energy to boil into steam at 373 K? The latent heat of vaporization of water is [tex]$225 \times 10^3 kg^{-1}$[/tex]. A. 0.0088 kg B. 0.24 kg C. 0.88 kg D. 1.13 kg

[Done] In a scenario where a thin metallic strip on a vernier calliper descends from the upper edge to the lower edge and makes contact with the surface of a beaker, the main scale displays a reading of 6.4 $m$ with a vernier constant of 0.1 mm, and the fourth vernier scale division aligns precisely with a main scale division. Determine the precise depth of the beaker, assuming there is no zero error.

[Done] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Done] Describe the real-world examples of Newton's third law that were identified in "Applications of Newton's Laws."

[Done] What is frequency a measure of? A. The height of the wave B. The speed of the wave C. The number of waves per second D. The length of the wave

[Done] Which equation shows how wavelength is related to velocity and frequency? A. [tex]$\lambda=v \times f$[/tex] B. [tex]$\lambda=\frac{v}{f}$[/tex] C. [tex]$\lambda=\frac{f}{v}$[/tex] D. [tex]$\lambda=v+f$[/tex]