Featured contributor PhD Applied Physics; former research associate at a national metrology lab.

Dr. Helena Ortiz

Senior Reviewer, Science & Engineering

0 calculators 0 articles Member since Jun 2026

About

Helena is the senior technical reviewer for physics, chemistry, and unit-conversion calculators. She is the last pair of eyes on every formula — checking constants, units, and edge cases against primary sources and standards bodies.

She holds a PhD in Applied Physics and previously held a research post at a national metrology lab.

Areas of expertise

Physics Chemistry Unit conversion Measurement standards

Education & credentials

BSc Physics — Universidad Complutense de Madrid
PhD Applied Physics — Stanford University

Physics / Electricity

Magnetic Flux Through a Planar Loop Calculator

Compute the magnetic flux Φ through a flat loop of area A placed in a uniform magnetic field B at angle θ between the fi...

basic

3,854 4.9 1 min

Physics / Electricity

Faraday Induced EMF from Flux Change Calculator

Compute the average induced EMF in a coil of N turns when the magnetic flux changes from Φ₁ to Φ₂ over time Δt: ε = −N ·...

basic

20,901 4.5 1 min

Physics

Apparent Magnitude Brightness Ratio Calculator

Compute the brightness ratio of two stars from their apparent magnitudes using Pogson's relation: F1/F2 = 10^((m2 − m1)/...

basic

681 4.7 1 min

Physics

Thin Lens Image Distance & Magnification Calculator

Calculates image distance, magnification, and image type (real/virtual, upright/inverted) from object distance and focal...

basic

17,816 4.0 1 min

Physics

Lens Power in Diopters Calculator

Compute the optical power of a thin lens in diopters from its focal length: D = 1 / f, where f is the focal length in me...

basic

8,300 4.7 1 min

Physics

Heisenberg Uncertainty Calculator

Compute the minimum uncertainty in momentum (Δp) and velocity (Δv) of a particle of given mass when its position is cons...

basic

21,957 4.8 1 min

Finance / Investing

Cost of Equity from CAPM Inputs Calculator

Calculates the cost of equity using the Capital Asset Pricing Model: r_e = R_f + β × (R_m − R_f), where R_f is the risk-...

basic

24,275 4.9 1 min

Chemistry

Clausius-Clapeyron Boiling Point Shift Calculator

Uses the Clausius-Clapeyron equation to find a new boiling point or vapor pressure at a different temperature given the...

basic

11,733 4.7 1 min

Health

Cardiac Index from Cardiac Output and Body-Surface Area Calculator

Compute the cardiac index — the bedside hemodynamic measure that normalises cardiac output to body size. CI = CO (L/min)...

basic

14,159 4.6 1 min

Physics / Electricity

Electric Flux Through a Flat Surface Calculator

Compute the electric flux through a flat surface of area A in a uniform electric field E, where θ is the angle between t...

basic

20,918 4.3 1 min

Chemistry

Debye-Hückel Limiting-Law Activity Coefficient Calculator

Compute the mean-ionic activity coefficient γ of a dilute aqueous electrolyte at 25 °C using the Debye-Hückel limiting l...

basic

8,974 4.9 1 min

Physics / Electricity

Magnetic Dipole Torque from Moment and Field Calculator

Compute the torque on a magnetic dipole (current loop, bar magnet) of magnetic moment m placed in an external uniform ma...

basic

7,606 4.4 1 min

Showing 49 to 60 of 504 results

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Reviewed by Dr. Helena Ortiz

These calculators were technically reviewed by Dr. Helena Ortiz for accuracy.

Chemistry / Reactions

Equilibrium Constant Calculator

Compute the equilibrium constant K_c from the concentrations of two products (with stoichiometric coefficients 1) divide...

basic

5,060 4.0 1 min

Conversions / Length

Length Converter

Convert between meters, kilometers, miles, feet, inches, and yards.

Featured basic

4,964 4.2 1 min

Chemistry / Solutions

Combined Gas Law Calculator

Find the missing pressure, volume, or temperature using the combined gas law for a fixed amount of gas.

basic

5,360 4.2 1 min

Physics / Electricity

Capacitance Calculator

Compute the capacitance of a parallel-plate capacitor from plate area, plate separation, and the dielectric constant.

basic

12,524 4.1 1 min

Chemistry / Solutions

pOH Calculator

Compute pOH from hydroxide ion concentration and the matching pH at 25 °C.

basic

18,221 4.2 1 min

Ecology / Carbon Footprint

Carbon Footprint Calculator

Estimate your annual personal CO₂e footprint from home energy, driving, flying, and diet — with adjustable emission fact...

Featured basic

15,825 4.9 1 min

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Dr. Helena Ortiz

Magnetic Flux Through a Planar Loop Calculator

Faraday Induced EMF from Flux Change Calculator

Apparent Magnitude Brightness Ratio Calculator

Thin Lens Image Distance & Magnification Calculator

Lens Power in Diopters Calculator

Heisenberg Uncertainty Calculator

Cost of Equity from CAPM Inputs Calculator

Clausius-Clapeyron Boiling Point Shift Calculator

Cardiac Index from Cardiac Output and Body-Surface Area Calculator

Electric Flux Through a Flat Surface Calculator

Debye-Hückel Limiting-Law Activity Coefficient Calculator

Magnetic Dipole Torque from Moment and Field Calculator

Reviewed by Dr. Helena Ortiz

Equilibrium Constant Calculator

Length Converter

Combined Gas Law Calculator

Capacitance Calculator

pOH Calculator

Carbon Footprint Calculator